Thursday, December 17, 2009

On My Windows & Weatherization Soapbox

Windows and weatherization have been in the news a lot lately with President Obama pushing a for Americans to make improvements to the energy efficiency of their homes. He's spoken a lot about replacing windows, and not so much about repairing existing single-pane windows or making small changes that will improve their efficiency. This is at odds with his other "green" initiatives, and seems to be the result of much lobbying from the replacement window industry.

There are several problems with replacement windows from a "green" perspective. Primarily because no one from the replacement window industry talks about the entire energy life-cycle of a replacement window that includes manufacturing the window, transporting it, and disposing of it when its useful life is over. Here are some "green" issues to consider:

  • They are expensive - with estimates for payback periods through energy savings of between 20 and 40 years (and some even longer). And guess what...the windows won't last that long, so you'll be on your next set of replacement windows before you're done paying for the first ones! (see below)
  • They cannot be repaired (maybe this is why they are called "maintenance free"!)
  • Their seals will fail after about 15 years - sometimes sooner - though it's usually after the warranty has expired. Then you'll need to replace your replacement window!
  • New windows require a lot of energy to manufacture, uses up natural resources (wood), and introduces toxic chemicals into the environment during the manufacture of vinyl, and again when the failed window is taken to the dump. They also have to be transported to your site - often from across the country requiring use of fossil fuels and adding to air pollution.
  • Wood used in new windows is "new-growth" wood. Because it grows so quickly, it's softer and less resistant to deterioration and insect damage than old-growth wood that was used to manufacture older and historic windows.
  • Old windows that are being replaced end up in landfills. Besides taking up space in the landfill, it can also introduce lead into the environment (you don't really think all those contractors are mitigating the lead paint before dumping those old windows do you?)
  • The money you spend on buying replacement windows leaves your local economy (unless you live in a town where a window manufacturing plant is located and buy them from a locally-owned retailer).
From a jobs creation standpoint, fixing up your old windows is far better than replacing them. It's a more labor intensive process than installing replacements, and the jobs are entirely created in your local economy. Caulk, glazing compound, and glass is pretty cheap - so are replacement sash cords - paying someone to do the work (if you don't just do it yourself) is good for your local economy, and generally good for your own wallet!

From a historic preservation perspective, it's pretty simple...They're not your original windows - they are a substitute. And they look like a substitute! They don't match the look of your house. Windows are very important in defining the character of buildings - change the windows and you'll dramatically change the appearance of your house.

In general, a much "greener" and better alternative is to fix up your original single-pane windows. Regardless of what the replacement window manufacturers tell you, single pane windows with a storm (interior or exterior) and some judicious use of caulk can be as efficient as a new replacement window. In some cases they provide better efficiency because the insulating factor of a window comes from the air (or other gas) between two pieces of glass. Since the space between a single pane window and its storm is wider than the space between two pane of glass in a replacement window, its insulating factor is higher.

Also, if you repair your old windows so that both the top and bottom sashes are working, then in warmer months when you raise the lower sash to let cool air in, you can also lower the top sash to let warm air out. This natural ventilation system will keep your house cooler and reduce those giant electricity bills for air conditioning!

The National Trust for Historic Preservation is on top of this window issue and is working to get the Obama Administration to understand it. They have a lot of resources available online for homeowners and other historic property owners. Check our their
Weatherization Guide for Older and Historic Buildings at

At our historic sites, we'll be tackling some window projects at the Amstel House after the holidays. The primary window project is the installation of interior storm windows throughout the building. These interior storms will help us with improving the energy efficiency of our historic single pane windows and limiting UV light to the interior (which damages objects over time). We'll also be doing our share of caulking as well as adding insulation to attics and cellars.

We're looking into scheduling a workshop to discuss storm windows and maybe glazing repairs sometime in January or February (stay tuned for more info about that).

Dutch House Logs

Our carpenters tackled the challenging replacement of a hand hewn joist in the Dutch House cellar last week. The original log joist was severly deteriorated - primarily due to old insect damage. the joist was supposed to be supporting the first floor along the west side of the building but really wasn't doing much of anything. The tenon of the joust was gone and the end of the timber was just floating.

The whole joist was not damaged - so we only need to replace about 12 feet of it. The section of the old log that had to be removed was cut into pieces with a chain saw. Here's a pic of the old log laying out on the curb...I think you'll see why we had to replace it!

The replacement timber is a hand-hewn oak timber that was salvaged from another historic structure. It was cut to rough size before carrying it into the cellar, and final cuts were made once the old timber was removed.

It sounds relatively straightforward, but the joist was located directly above the buildings main electrical panel, security panel and sprinkler system and all their associated wires. Oh yeah...and the gas lines and meter too. Earlier this year we had an electrician move the panel and loosen the wires so the carpenters had some room to work with - though not very much! Here's what it looked like installed:

The new joist needed a tenon on one end, and a lap joint on the other where it would be joined with the remaining section of the original joist. Here's pic of the completed lap joint (the new joint is coming in from the left side of the photo):

A new 6" x 6" post was placed directly beneath the lap joint for support. We also added a second 6" x 6" in to support another of the original joists nearby:

Once the joist was installed, shims needed to be used to fill the gaps between the uneven surface of the hewn log and the floor boards above. Here's a pic showing both shims and the tenon-end:

In addition to the replacement of this joist, the bulkhead for the cellar doors was reinforced with steel:

And that pretty much wraps up the structural work at the Dutch House, as well as the projects there in this phase of our work. When we finish the Amstel projects we'll see where we stand with funding and see if we can tackle some additional projects there.

Tuesday, November 24, 2009

Was it or wasn't it... in the 18th century?

That's the question we've been grappling with regarding a doorway between the original kitchen of the Amstel House and the second parlor - which functioned as a dining room during certain hours of the day in the 18th century. Here's a pic of the doorway (on the right) and the rest of the wall before we started our accessibility project. The original kitchen can be seen through the doorway beyond the hall:

On the near side of the doorway is some c. 1970 trim. On the far side of the doorway, there is no trim - instead the top of the opening is arched and finished in plaster. It reminds me of some arched doorways I've seen in local houses built in the 1920s and 30s. In my mind, this reinforces the idea that this wasn't an original doorway opening - at least not in its current configuration.

Here's some more background...

Here's a HABS drawing of the first floor of the Amstel House as it appears today. The doorway in question is the one with a red circle around it. It's also important to know that the two current windows that have green squares around them in the floorplan were doorways in the 18th century (we're confident of that!)
A few years ago we had an architectural historian examine the Amstel House, and he had insufficient evidence to be able to say for certain whether this doorway was original or not. If it was not original, there are pretty interesting implications for traffic flow between the kitchen and the rest of the house. Without this doorway, slaves or servants bringing food from the kitchen into the second parlor had to leave the kitchen through one green door and into the second parlor through the other green door, or go through the kitchen yard and enter the center hall through the rear door - either way, both they and the food are exposed to the elements. We offered this possibile scenario in our interpretation of the house though it has always been something that has bothered most of us here.

There are some clues in the nearby architecture that indicate that the wall that the doorway is part of was originally a paneled wall with built-in cabinets on either side of the fireplace. The clues include a break in the baseboard, change in floorboards, ghost lines in the adjacent plaster walls and ceiling, and a nagging sense that something just isn't right.

Here's some pics:

This pic shows the break in the baseboard. This wall is to the right of the doorway in question. There's a vertical line in the plaster directly above this break too, but you can't see it well in this small photo.

Here are two old floorboards still in place near the doorway. The joint toward the bottom of the picture lines up with the break in the baseboard above (you'll have to take my word for it).

Finally, there's a ghost line (more like a plaster crack!) in the plaster ceiling that lines up with the corner of the fireplace, the lines in the wall and baseboard and the joint from old to new flooring. All this evidence seems to support the idea that there was some type of cabinet in this location. The cornice, by the way, is 20th century - installed during an early restoration effort.

Similar evidence exists on the other side of the fireplace (remember Georgian symmetry):

So with all these things nagging at us, along comes our accessibility project this year. We decide that to give people that use wheelchairs full access to the first floor, we need to widen this doorway. Actually we just need to wide the c. 1970 visible frame of the doorway (no masonry involved). As we got underway removing the frame of the doorway we were able to see more of the masonry construction of the arch - and guess looks like the arch was built in as part of the original masonry! No obvious change in the brick units and no change in the mortar - the arch matches the wall nicely.

Here are a few pics of what we found:

The first pic shows the full arch masonry exposed. Then closeup shots of the left and right sides of the arch.

Next we examined the plaster. It was applied directly to the brick of the arch. It looks like the plaster had an early black painted finish on it:

Here's a shot from underneath the arch look up toward the ceiling. The black finish is pretty wide across the bottom of the arch. It may continue underneath the modern finish - we can't tell:

This black finish continues down the side of the doorway opening:

It also continues behind the current baseboard - indicating that there may not have been a baseboard in this location. Instead, the wall was painted black to mimic a baseboard. I've certainly seen this treatment in other 18th century houses (Yes, I'm looking at you, John Chad!) If this area was inside a cabinet, I think this makes a great deal of sense - particularly given the break in the baseboard noted above:

One other thing to note is that the two old floor boards (see photo way above) extend through the current doorway. If the doorway was not there in the 18th century, and it was a wall instead, the floorboards would stop at the interior side of the wall (their ends being covered by baseboard).

So with all this new information coupled with our old, nagging clues, we have a new theory on the design of this wall. I believe that the wall was fully paneled in wood, with a built-in cabinet with shelves on the left of the fireplace and a false cabinet on the right side of the fireplace where this arched doorway is. With the door of the false cabinet closed, it would conceal the arched opening into the kitchen while allowing quick passage between the two rooms as needed. This concept of concealing doorways, stairs, and passages is certainly something that is used in other houses from this period. In fact, it is used on the second floor of the Amstel House - directly above these two rooms and above this very doorway! I like this theory better and better!

Based on this new information, here's a modified version of the HABS floorplan that I mocked up to reflect what I think the first floor of the Amstel House looked like in the 18th century:
So is this the last word on this subject?

I doubt it. More information will probably come to light in the future...possibly through paint analysis that will help establish with more certainty what the first finishes are on the plaster in this area.

Until something else comes to light, we'll be incorporating this "conjectural" floorplan in our interpretation of the house, always being careful to use the qualifying phrase "Based on current research, we believe..."

A New Post!

OK, so I've been a bit slow at posting's been relatively quiet on the construction front around here. So that means its time to catch up. Here a few photos of the finished brick accessibility ramp and dry well area that we worked on last summer. Truth be told we still need to install a mahogany threshhold at the door to allow people that use wheelchairs to enter the building. But that's coming soon! Also, next spring we'll plant some grass in the area. We contacted our lawn service to get the same blend of seeds that they used a couple of years ago when the whole lawn was re-seeded.

In the photo above you can just make out the slight incline of the brick ramp as it rises in elevation from right to left. It's very subtle and we are very happy that the overall impact on the landscape will be negligible once the grass is growing in the area again.

This second photo shows the are of the drywell and the pipe trenches leading to it from the house. These areas will be reseeded in the spring. Just off-center to the left in the photo you can see a small bit of PVC pipe protruding from the drywell. This is a temporary pipe that we installed to check the level of water and rate of drainage in the drywell. You'll recall that we hit a layer of clay about 6 fe
et down and we're concerned about the drainage rate from the well. So far, after several pretty heavy rains in a short mount of time, the well is performing nicely. Now we just need a big nor'easter to give it a final exam (just kidding!)

Here's a shot up the new ramp toward the back door. You get a good perspective of what the height of the new threshhold going into door will need to be. Also, since this walk was an existing part of the landscape, our masons mapped the location of every brick when they originally pulled this walk up. When they laid it back down, all the bricks were placed back in their same location to the walk has exactly the same appearance from above.

Next...the controversial doorway!

Friday, October 9, 2009

Historic Windows Workshop, October 24

On Saturday, October 24, from 10 am to Noon, the New Castle Community History and Archaeology Program (NCCHAP) will sponsor a workshop at the Read House on historic window repair. Workshop participants will observe the removal of historic window sashes and components such as weights and pulleys. Carpenters will discuss the repair of sashes, frames, and sills. The Read House Save America's Treasures project restoration architect will also discuss the repair of historic windows and the Read House project.

Space is limited; please call 302-322-8411 to register.

This workshop will be complemented by another workshop offered at the Amstel House focusing on the benefits of storm windows and other techniques for improving energy efficiency.

Time Flies!

Wow! It's October already, and I haven't had a post on here since August! Time to catch everyone up one what's been happening!


This is where we left our story in August. The masons arrived and pulled up all the bricks from our rear walkway, recorded their position, and began to did a few trenches for drainage pipes that will lead to the dry well.

Drain pipes that will gather water from two new downspouts at the rear of the building were installed. They convey the water to the drywell - an 7' deep hole in the backyard filled with 3" stone - where the water will safely disburse underground. After the pipes were laid, the trenches were backfilled with gravel and/or dirt. Along the side of the house, a membrane was used to line the trench to prevent any possible leak from impacting the building.

Here's a couple of pics. The first shows the empty trenches that were dug by August 19, and the second shows the trenches backfilled and the height of the pipes when they reach the dry well.

Exterior Accessibility

Once the pipes were installed, the roofers returned to install new gutters and downspouts. We now have two downspouts instead of just one at the rear of the building and the gutter has been pitched correctly so the water won't run towards the building anymore (that's a bad thing!). The gutters still need to be painted however.

Next up comes relaying the brick walk our back. But we want to create a ramp up towards the back door so that the museum will be more accessible. As I write this today, the masons are just finishing up the new walkway. Here's a few pics of what the walk looked like as of Wednesday:

At the point where the brick reaches the door, our carpenters will fashion a ramped threshhold out of mahogany or cypress to make the transition up into the museum shop area. The masons are currently working on the transition from this ramp to the patio out of frame (to the left of the bottom picture).

Interior Accessibility

Inside the building we had to make some minor modifications as well in order to allow someone that uses a wheelchair to make their way throughout the whole first floor of the building.

We added a small threshold in the doorway from the museum shop into the kitchen hallway. It is made out of salvaged antique pine and should eventually darken to match the historic flooring in the hallway. Here's a pic:

Once in the hallway, a ramp is needed to get up into the second parlor or dining room of the house. That ramp was also built from salvaged antique pine. One task still left to do is to round over the edge of the ramp where it meets the floor. Because we installed the boards parallel to the existing floorboards it's possible that someone could chip the end grain if they kick it or drag their feet.

Finally, we also had to widen the doorway into the second parlor to achieve a width of at least 32" to allow a wheelchair to manuever through the doorway. This did not require us to alter any historic fabric. The doorway had been framed in the 1970s so we just widened that 1970s era framing. Since we widened the door, a new piece of molding had to be milled for the top of the doorway to match the existing molding on the sides. The door was removed completely, tagged as to its location in the second parlor, and placed in storage. Here's what the doorway looks like now:

This doorway has been a controversial architectural feature for some time now - we weren't sure if it was original or not. When we removed the 1970s doorway framing we had a good look at the construction of the doorway. I'll describe our findings in a future post!

Monday, August 17, 2009

Landscaping Begins

Today, carpenters and masons from our general contractor arrived on site to continue our projects at the Amstel House.

The carpenters will be applying painted trim boards at the top of the rake boards at the gable end of the the Amstel kitchen wing and the south side of the Dutch House. The trim board is simply a 1" x 2" that will be fit directly beneath the edge of the new roofing shingles to cover the gap that is created by our layered roofing system (about 1/2"). While the trim board is not an historically accurate ele
ment of either house, it is completely reversible and will protect the roof sheathing while giving a finished appearance to the rakes. It allows us to install a roofing system that has a Class A fire rating instead of a Class B. So we are willing to add the new element for the overall protection of the structures.

The masons are here to develop a materials list for their accessibility and drainage project at the rear of the Amstel House. They will begin removing bricks from the walkway at the rear door of the building (the museum shop door). they will be pulling all the bricks up individually and mapping the individual location of every brick so that when they put the walk back down, the bricks will be in exactly the same configuration that they are currently in.

Between taking the bricks up and putting them back, they will install underground drainage pipes to carry roof water from the downspouts to the new dry well in the center of the yard. Then they will regrade the area to create a gentle slope up to the rear door that will meet ADA requirements and allow people that use wheelchairs easy access to the museum.

Speaking of digging holes and walkways....

I need to provide an update about what the archaeologists found. The big finds were a few post holes that might indicate the location of a fence in the back yard, and a brick walk that was discovered about 18 inches below grade where we are going to be placing one of our drain pipes. The post holes could be 18th century - we're not sure of the age of the brick walk - though earlier surfaces were discovered in the trench at deeper levels. Here's a pic of the archaeologists uncovering the buried walkway:

Tomorrow I'll post pics of the completed trim boards on the rakes.

Wednesday, July 29, 2009

Digging"For" China

The next project on the docket at the Amstel House is our drainage and accessibility project. The project includes two things:

1) Regrade the area at the back door of the building to create an
accessible entrance to the museum; and

2) Provide a drainage system to get the water fro
m the roof away from the building without impacting the landscape in the long term.

To accomplish the drainage goal we will be installing a dry well in the backyard. water from gutters will travel vis two downspouts to an underground pipe that will carry the water to the dry well. The water flows into the buried dry well and disburses underground where it will not infiltrate the building and will not damage the landscape.

The hole for the drywell is 6' x 6' x 8' (w x l x d ). before we start the project we need to investigate the site of the dry well with the help of a professional archaeologist to determine if there are any archaeological resources in the ground there.

We put a call out for volunteers to assist and this past weekend we started our archaeological dig. On Saturday we had two professional archaeologists and 7 volunteers here, and on Sunday we had one archaeologist and 4 volunteers here. Here's a photo of our progress excavating by mid-Saturday afternoon.

Some of our volunteers have worked on archaeology sites before, but some of us (like me) are newbies. Tim, our lead archaeologist, kept us all straight though. I spent most of my time sifting through buckets of soil looking for the elusive great find. We had two sifting tables working all day:

So far, we've found a variety of artifacts spanning about 200 years of site history (going back to about the turnof the 19th century - we think). Everything from building materials to broken ceramics. We'll continue the dig this coming Saturday, as we hope to reach the 17th century. The Amstel House site was owned by Roeloff de Haes, one of New Castle's early Dutch settlers, so anything we find will add to our knowledge of how the site was used during the second half of the 17th century. Of course to get to the 17th century, well need to dig through the 18th century, and that will yield information about the first century of the Amstel House's existance - our primary period of interpretation in the house.

Before Saturday though, my project is to get rid of the big pile of dirt that is now sitting on the back patio - a result of our sifting process. I've already saved some topsoil for future garden use - now I just need to get the rest of the dirt out of here!

Roof Finished

The roofers pretty much finished work at the Amstel House on July 18th and everything looks good. We will have a meeting this coming Friday with our architect and the general contractor to review a punch list of items to be finished at both the Amstel and Dutch Houses - primarily gutter work and the installation of a diverter over the Dutch House cellar doors - then the roofers will be finsihed with us.

Here's a couple pics of the finished roof and flashing at the Amstel House:

You may have noticed in thelast photo that the flashing covers the drip course on the chimney. We debated about this treatment after it was done, and discussed whethere that was the best way to handle it. Ideally, the flashing should have been installed beneath the drip course (with a reglet cut in the mortar joint just under the drip course), but with our layered roofing system there realy was not enough room to do that effectively - so we are going with what we have here.

All in all the roof looks great! And everything is dry inside!

Friday, July 17, 2009

Back To Our Regularly Scheduled Programming...

The roofers have been at the Amstel House for three days now working on the roof of the kitchen wing and the small pent roof on the Fourth Street side of the house. They may wrap up late this afternoon.

The did one side of the roof each day beginning with the east sid
e. Here's a pic of the roof on the kitchen wing late Wednesday afternoon:

On Thursday they worked on the west side of the roof. they had to stop briefly mid-day for a pretty heavy shower, but were back on the roof shortly thereafter. Here's another late-day pic:

They arrived this morning and immediately started on the pent roof on the front of the house. It's basically three courses of shingles to protect the big cove cornice that runs between the second and third stories of the house. I took the opportunity to take a few pics once the shingles were removed from the pent roof since we don't generally get a chance to see the construction of this area. In the following pick you can see the sheathing that exists under the shingles of the pent roof. No flashing is used in this situation because the shingles tuck up under the projecting bricks of the belt course (you can just see this to the left of the man's arm in the photo). No plywood or cedar breather will be used either.

While some of the crew worked on the pent roof, on roofer was working on the flashing around the kitchen chimney. You may recall that the roofer decided to go with traditional step flashing instead of the lower-profile flashing option recommended by the masons. This is how the chimney looked at about noon today.

Since the roofers were working above each entrance to the building we closed the Amstel House today. I had hoped we would re-open it late this afternoon but as of now (3:10 pm) they are still cleaning up the area under the pent roof and working on the kitchen roof. We'll be back to business tomorrow!

Civil War Battlefield Threatened

Please forgive this side trip to Virginia discuss an out-of-state preservation issue. Normally the mantra of preservation is think globally and act locally but I think this is an issue that has national significance and warrants stepping outside New Castle for a bit.

It's been dubbed the "Wilderness Walmart" after the Civil War's Wilderness Battlefield which is threatened by a proposed Walmart across the street. More specifically, Orange County, Virginia is considering a proposal to build a 138,000 sq. foot Walmart SuperCenter in a 51.6 acre development within 1/4 mile of Fredricksburg and Spotsylvania National Military Park (which includes the Wilderness and Chancellorsville battlefields in addition to Fredericksburg and Spotsylvania).

For a brief history of the Battle of the Wilderness click here.

The County is in favor of the development because it will provide jobs and tax revenue. Preservationists argue that the development will hurt the long term preservation of the battlefield, and alternative sites are available that are more appropriate for the WM Supercenter. Building at a different location will still provide the jobs and tax benefits that the County desires.

I've been following the story for quite a while, but since the Historical Society visited Gettysburg last month it has risen higher on my radar screen (you may have heard about the proposal to build a casino in Gettysburg which was defeated).

Click here for a map of the battlefield and proposed Walmart location.

I decided to post this because earlier this week the Virginia governor Tim Kaine (D) and House of Delegates Speaker William Howell (R) sent a letter to the Orange County Board of Supervisors urging them to reconsider plans to build the Walmart on land adjacent to the battlefield, and look for an alternative site. Kudos to these state officials for reinforcing Virginia's long record of historic preservation throughout the state.

National preservation organizations have also weighed in. You can read their positions on the controversy here:

Civil War Preservation Trust

National Trust For Historic Preservation (NTHP)

If you want to voice your support for the protection of the Wilderness Battlefield and finding an alternative site for the Walmart there are a few things you can do:

Sign the NTHP's online petition here.

Send an email message to Orange County officials here.

To keep up with the story, I recently added another blog to my blogroll here. If you scroll down the screen you'll see it on the right side listed as "NO WILDERNESS WALMART." It's a blog opposing the construction of a Walmart Supercenter across the road from the Wilderness Battlefield in Orange County, Virginia.

Wednesday, July 15, 2009

Be Nice To Your Historic Brick!

One of the members of our historical society missed our June fireplace/chimney workshop and contacted me via email with a follow-up question about the best way to clean mildew/algae/moss from historic bricks (a common problem around New Castle). It affects a wall of her house that borders a shady alleyway. She also asked if using a sealer on brick might be a good way to keep water from driving rains from penetrating her home’s brick walls.

She suggested that I add my response to the blog - a great idea! So…here’s a summary of my response to her:

In general, for historic brick it is always best to use the gentlest means possible for cleaning. That usually means just water and a natural bristle brush. You can try that if you haven't yet, but sometimes staining doesn't respond to that so here are a few solutions that our mason recommends (listed from gentlest to harshest – though all should be safe for historic masonry):

Vinegar and water – though he didn't give me a ratio for this - I'd start with one part vinegar to one part water and increase the vinegar as necessary.

Bleach and water - start with one cup of bleach to one gallon of water. Increase bleach slowly if necessary.

Muriatic acid and water - one part muriatic acid to 10 parts water (Remember when mixing these together to add the acid to the water. Don't add the water to the acid or else it might boil and spit acid on you. Ouch!) FYI...The masons used this solution to wash down our chimney at the Amstel House to remove excess lime from the bricks and mortar, and also to clean the salvaged bricks before using them.

Whichever of these solutions you try, its a good idea to test it first on a small section of the wall and let it weather for a while before going on with the whole project. Always better safe than sorry!

Whenever a discussion of cleaning brick comes up It’s worth noting that there are two cleaning methods that should always be avoided - powerwashing and sandblasting (which is about the worst thing). These methods are generally too harsh for historic brick, and will destroy the hard outer surface of the brick. Don’t let anyone talk you into using these methods on your historic brick (or any other historic materials for that matter!).

Regarding the second question…It's almost always a bad idea to apply any type of exterior sealer or coating (including paint) to historic masonry. Historic masonry - particularly if it was built with lime mortar, needs to breathe to allow water vapor to pass through the masonry to the exterior of the house. Water gets inside walls from a variety of sources including driving rain, condensation, rising damp, etc. I should mention that an exterior sealer will keep driving rain out - but it won't do anything about water in the walls from condensation or rising damp - it just makes those issues worse.

Any water in the wall needs to get out of the wall somehow - normally that's through the exterior mortar joints. If you seal up the exterior surface the water will escape through the next easiest path - usually that is through your interior wall surface which is typically plaster or drywall. So you'll eventually start to see plaster failure on walls that have an exterior sealer. The same thing can happen if you re-point your historic brick with a portland cement mortar instead of a lime mortar since portland cement is so hard (it also will cause your historic bricks, which are softer than the portland cement, to fail).

In looking around the web, you may find that there are some sealers that claim to be breathable (usually these are siloxane-based sealers). They look promising, but don't have a long enough track record to recommend them on historic buildings yet. One of these was actually applied to the garden house at the Amstel House and I'm pretty nervous about it - I'll let you know how it's going in about 10 years. One problem with all sealers is that once they are on the brick they are not reversible. Any sealer that is silicone-based is one that should be avoided at all costs.

If you have any painted woodwork on the wall that has been affected by mildew, a safe cleaning mixture is one cup bleach to one gallon of water. That's very diluted so if it doesn't work right away you can add more bleach a little at a time. Again use a natural bristle brush to do the cleaning. I've used this on the windows at the Amstel House with good results - though I need to do it again (ugh!).

If there is any way that you can trim branches to allow more sunlight into the area or increase the airflow to the alley that might help retard future growth. Also, it might be helpful if during the next heavy rain you take a look outside to see how the water is draining away from the area, if you are getting any splash up onto the walls from roof or gutter water, of if the gutters are working correctly.

Finally, here’s a link to an article from the National Park Service on cleaning historic masonry ( It should help with the basics though I don't think it covers mildew/algae specifically. The Park Service has a whole series of these articles about various maintenance topics for owners of historic houses. You can see and download them all for free at

Always remember...Be Nice To Your Historic Brick!

Catch Up Time

It's been a while since we've had a post - mostly because it's been pretty quiet around here. But I still need to catch you all up with what has been done.

Before and after the Fourth of July weekend, the masons completed their work on the west chimney. They replaced around 50 bricks, dismantled and relaid the crown of the chimney, and re-pointed the whole thing down to below the shingles.

They also parged the inside of the flues from the top down as far as they could reach - about 3 feet.

Like the kitchen chimney, this one had a void in the masonry between flues - posing a fire hazard if the fireplaces were ever used.

Since the void was visible, we decided to fill the cavity with the same vericulite/cement mixture that we used on the kitchen chimney. Again, our thought process was to incure the long-term survival of the building. We found a problem so we addressed it rather than cover it up. If the house ever has a different owner that tries to use the fireplace, we don't want them to have a bad experience!

Finally, they capped the chimney with metal that slopes from the center down toward each side to shed rain (it's shaped like an upside-down "V", except much flatter). They installed temporary flashing that will be removed once the roofers are ready to build a cricket to protect the chimney.

The chimney was out of level by 2.75" across the width at the top - pretty bad considering it's only about 5 feet wide. They were able to correct it by using some slightly thicker bricks and increasing the size of the mortar joints slightly. The trick was to do this in a manner that would be imperceptible from the ground. In the following pic you can see that the courses of brick rise from the left side of the chimney to the right side:

The results are great - the chimney looks excellent with the chimney mortar matching the adjacent gable end mortar perfectly.

So the next project is the roof on the Amstel House kitchen wing. The roofers arrived today, and the tear off process has started. As I write this, they have removed all the shingles from one side of the house and are in the process of installing plywood over top of the lath.

We're using the same installation process that was used at the Dutch House, so I won't rehash that again here.

The wood shingles will be standard "royals" with a normal thickness - no tapered butt like we did at the Dutch House. We are matching the shingles that are in place on the roof of the main block (that roof is not being replaced since it has several years of life left in it).

In addition to the roof, we'll also be correcting some gutter issues and completing some minor repairs to the metal roof that is on the 1905 rear addition. the roofers should be on-site for about a week - barring any weather-related delays.

Gotta run - I'm expecting our architect to arrive any minute to inspect the Dutch House and check out the progress thus far at the Amstel House.

More tomorrow!

Thursday, July 2, 2009

Sharing What We've Learned

June 29

Tonight is our NCCHAP workshop on fireplace and chimney preservation. But before the workshop, I will meet with our architect and mason to discuss our current progress.

The masons were not on site today, pending the outcome of the
meeting above. The roofers were at the Dutch House though and were making progress on the roof. The owner of the roofing company came out mid-day to take a look at the progress.

Later in the afternoon, our architect had a look at the roof and was generally pleased with the progress though needed to address some flashing installation issues with the roofers. It seems that they cut a reglet into the brick rather than into the mortar. This weakens the brick so the architect told them to re-cut the reglet in the mortar, making sure that their previous reglet was fully covered by the flashing. Unfortunately, we now have some cuts in the chimney brick that are unnecessary. However, at least they will not be visible once the flashing is correctly installed - though the flashing itself may be slightly higher t
han it would have been if done correctly initially.

The evening workshop went well with 25 people in attendance (SRO). Here's a couple of pics from the workshop:

I've received nothing but positive comments about the workshop with several people mentioning that it will help them with their own projects. We'll be hosting more of these types of workshops as we begin to tackle other projects that face many historic homeowners. Keep an eye on our website's calendar of events page for more information about these workshops.