One of our friends writes and asks about a historic home that they have recently purchased that has some problems around one of their windows. The window has actually been replaced and it is functioning but the sill of the window / bottom window ledge is sagging pretty bad. A few professionals had the chance to look at the problem when he was making the purchase and didn’t believe it was something that was recent. The problem they have is how do they make a repair of the window sill to make it look better and what this might entail.
The first thing you should remember whenever you run into things like hairline cracks in your foundation or walls or maybe settling of this type is when did the problem start and is it getting worse. Since this is a historic building this could have happened 75 years ago and no additional damage may have occurred since.
The rule of thumb is if it has not changed in the past 6 months then you are likely to have a problem that has stabilized its self.
With older homes like this you are never guaranteed about how construction was performed. The building could have had professional contractors or it could have been built by the home owner or a mixture of the two. Not only that you have to consider any additional work that has happened since.
The worst problems with windows is when they leak. They can leak directly on to your floor or they can leak internally because of the way the flashing or siding has been performed when the window was installed.
Another problem that happens way too often is when you have a roof leak that runs down a wall internally and the problems don’t show up where you would think the leak is actually occurring. These problems often result in many visits from many contractors that guarantee the problem has been fixed but in a few weeks it comes back.
All of this points to one thing. The quality of home building must be of a level that ensures all parts of the home are protected from failures from other parts. If something goes wrong you should be able to find the problem but often it requires a contractor with many years experience to know that he is going to have call back after call back and only in this way do they learn where to really look for the problems.
I would expect that the problem with this window is a mixture of framing and water leaking. Water that leaks into the internal wall framing over time will cause the wood to rot.
How To Attempt To Cure This Problem
Since it is a historic building it might be ok to leave the problem and consider it a battle scar of age. On the other hand if the home owner just can’t live with it and the problem is pretty bad there is only one thing to do.
Start by removing the plaster and lath below the window and you should see what happened to the internal structure of the wall. You can cut an inspection hole but you should go wider than the window so you can see the king and cripple studs used to frame the window opening and also you want to see the bottom wall plate to see if there is any rot or other problems.
Most likely the window will need to be removed and then new framing and molding installed and then the window can be replaced.
This is not easy work and it could point to other problems which you will end up having to fix.
Another option for this home owner is to cut the window sill with a saw and then frame in some molding material to make the damage look less obvious. This is probably the best step if other professionals have given the ok that the sagging is historic and not recent.
They should be able to take out a good half to 75% of the sag look and not have to open the wall but it will never be perfect.
They could even mud the area with a fiberglass resin body filler used in automotive applications and fill even more of the sag.
Historic homes are always going to be a problem because they were built using materials that are not normally used today which are not standardized. You need to take this into consideration when you make your purchase that you aren’t moving into a brand new sky scraper made of steel and glass.