My window jamb... is... crumbling! How do I fix it?
November 2, 2013 1:46 PM   Subscribe

My mother's house has these recessed casement windows, and the mystery material the jamb (or maybe jamb extension?) is made of has started to crumble. Whole chunks come out when I put the air conditioners in each spring and take them out every fall, and forget about keeping the window shade hung -- I have yet to find an anchor that won't get pulled out. I'm going to take a stab at fixing it while I'm home for Thanksgiving, so I need help devising a plan of attack that can definitely be completed over a four-day weekend, even if that means it's just a stop-gap band-aid-type repair.

Here are some more pictures. Sorry they're not clearer -- my sister took them because I'm on the other side of the country.

I'm honestly not one-hundred percent sure what the material is, or what's underneath it. Over the years we've discovered that the builders have used some... let's call it "idiosyncratic" techniques. It seems like there's a really thick layer of gray plaster over everything. On the top jamb of the window, around six inches deep, is either some sort of seriously hard wood, or possibly brick? My cordless drill can barely bore into it, and the dust that comes out when I try is reddish. On the sides... I'm not quite sure what's going on. (The red color there is an old layer of paint.) It seems like there's a layer of something that's pulling away from the wall en masse.

So, yeah... does anybody have any guesses as to what's going on here? Ideally, I'm looking for help coming up with a plan for a quick stop-gap repair, but even just being told what the right terms are for the type of construction so as to make for easier googling would be helpful.
posted by patnasty to Home & Garden (10 answers total)
I'm not quite sure how I'd go about repairing this, but... it looks a lot to me like the mystery material is spackle? Any idea what they'd be laying that spackle on top of?
posted by Andrhia at 2:10 PM on November 2, 2013

Are the black spots mould? The good answers here will probably want to take into account whether or not there's a water/moisture issue in the mix. Run some caulk around the outside as a precautionary measure?

I (not an expert, just a person in an old house) would look for a product like this wall and floor repair mortar, or this U-Can Brick & Wall Repair Mortar, and trowel that on and hope for the best.
posted by kmennie at 2:20 PM on November 2, 2013

How old is the house? Where is it? Those can be good clues into what materials may have been used.

That said, looks like plaster to me. If there's a water issue, that could cause all the disintegration.
posted by gnutron at 2:38 PM on November 2, 2013

Those look like old steel-framed casements. The jambs are basically solid steel strips that surround the rough opening. A layer of plaster has been applied to give a smooth surface to paint, and to give a nice transition from the jamb to the wall. Take a putty knife and clean away any crumbly/cracked finish, and re-apply drywall mud. Paint to finish. Unfortunately, putting in and removing AC units is probably always going to be an issue.
posted by Benny Andajetz at 2:40 PM on November 2, 2013

I'm kind of with Benny Andajetz on this, with one additional provision. Above the window, there should be some kind of lintel, usually a single piece of angle iron or stone, of sufficient thickness to carry the weight of roofing and load above the window out to the load bearing studs on the sides of the opening, which then carry the load down to the ground. If there is a water intrusion problem that has begun to rust the steel window casements, you'd want to check the condition of the lintel, too, particularly if it is an angle iron one, to be sure that it is not rusting through, diminishing its strength as a framing member. And you do not want to be drilling willy-nilly into a lintel, or any other framing member, which might weaken it, or be a starting point for corrosion or insect damage.
posted by paulsc at 3:06 PM on November 2, 2013

You'll want to carefully examine the outside flashing around the window and the general vicinity above it to see where water might be getting in. Get some silicone in an appropriate colour and caulk around it. Then you can scrape of the flakey plaster and re-spackle.
posted by bonobothegreat at 3:19 PM on November 2, 2013

Response by poster: Thanks for all the replies so far!

So, the house is in a suburb outside of Boston, MA, and was built in 1953. Aside from the crumbling issue, there aren't really any signs of a major water issue. Rain doesn't get through when the window's closed, and there isn't any visible water damage on the wall and ceiling above the window. The window is directly above the sink and the dishwasher, if that makes a difference.

How aggressive do you think I need to be about stripping away the old crumbling stuff? And if it turns out that the rot goes all the way down to whatever the frame is made of, would refinishing the thing entirely anew still be an amateur DIYer level project? I'm concerned about getting in over my head and having to call a contractor to fix the mess I've made.
posted by patnasty at 6:34 PM on November 2, 2013

There may not be a major water issue but it only takes a tiny bit of water, making it's way into the wall every time it rains, to make the building materials punky and soft. Double check the top side of the flashing (the frame surrounding the outside of the window) for small gaps.
posted by bonobothegreat at 8:06 PM on November 2, 2013

"... Aside from the crumbling issue, there aren't really any signs of a major water issue. ..."

Yeah, but... The pictures show a lot of crumbling stuff. 60 years is a long time, but plaster/dry wall/whatever should be pretty inert stuff, in a protected, dry environment. There are plaster and lathe walls around double hung windows in houses in nearby Waltham, built in the early 1800's, that have a few cracks from foundation settlement, but no crumbling.

You've got to look for what's wrong, not what's right. As bonobothegreat says, it only takes a few drops of water, at every rain storm, to make a mess over 60 years.
posted by paulsc at 8:19 PM on November 2, 2013

"... I'm going to take a stab at fixing it while I'm home for Thanksgiving, so I need help devising a plan of attack that can definitely be completed over a four-day weekend, even if that means it's just a stop-gap band-aid-type repair. ..."

Let me suggest that instead of trying to fix everything in one 4 day weekend, as a DIY amateur, that you pick just one window with the problem, check inside and outside with a smoke candle for leaking air around the casing ("none whatsoever, in either direction" is the right amount of leakage air), and be prepared to dig out the cracked plaster, pull any nails/screws holding the casing, and actually remove the whole window from the surrounding frame, to get a good look at all the framing around it. Have a camera handy, so you can take pictures as needed, to show the folk at the big box store from which you'll be getting repair supplies and further advice. With luck, you may be able to remove some trim and a little siding on the outside, replace some flashing or casing, caulk like crazy, replace the existing window and secure it with nails or screws, nail up the outside trim you removed, and do a little replastering and repainting inside.

Without luck, you may need to call in a contractor, for more than 4 days, to fix rotted framing, stop larger water leaks or insect damage, and repair the windows, plus all the stuff above, at each window affected, as well as do incidental repairs like replacing rotten sheathing under external siding, and re-insulating. Good luck.

Again, look for what is wrong, not what is right.
posted by paulsc at 10:31 PM on November 2, 2013

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