We’ve used this same firm for at least 10 years to maintain our current boiler, which has a small tank at the bottom and so sits on the ground. It looks like we’ll need a replacement soon, and of course we want to put it near where the old one is (to take advantage of all the current fittings etc.), but the new one won’t have a tank so it is designed to hang on a wall. The wall is off the garage in a space under the front stairs (the stairs run up across the front of the house). The inside of the wall is bricks; the outside is stucco. We can’t see what, if anything, is between the two. The house was built in 1949.
I was thinking that since the brick wall is only supporting the outside end of the stairway and small porch, it might not be as sturdy as a regular brick wall. Plumber thinks it will be fine, he says the boiler will weigh around 50 pounds.
Should I get some kind of expert in, in advance, to see if this idea passes muster? Or will the city inspector do that (at which point we might have wasted a lot of time and money). What if we built a structural wooden wall inside the brick wall, would that cover the need? Am I over-worrying about this?
As a general matter I’ll agree w @Gatopescado. But the OP is in San Francisco. Earthquakes and special building codes are common there. That might be a difference worth asking specifically about. It’s probably difficult to talk directly to a city building inspector, but that’d be the ideal source.
I would ask the plumber directly if he’s getting a permit for the work. It might or might not be required. If he’s not, there won’t be any city building inspection. There’s nothing wrong with no inspection of non-permitted work where a permit isn’t required.
And how much weight is on it when you’re walking up the stairs?
What kind of brick are we talking about? If it’s something like cinder block, I wouldn’t be at all concerned. If these are ‘normal’ bricks, like the standard sized ones you’d see a house (exterior) made of, I might be a bit more concerned but that would also depend on the mounting system.
If you’re really concerned, you could mount some 2x4s or unistrut on the wall, but have it go up high enough to attach it to the floor joists above the wall. That way a good chunk of the load is being supported by something other than the brick you’re concerned about.
I’m picturing something like this. Maybe not exactly like this, but a frame similar to that made from wood or metal and mounted not just to the wall but the floor joists above. And, yes, I know that’s a poured concrete wall, not actual bricks, but that’s irrelevant. Incidentally, it was harder than I thought to find a picture like this because most pictures just showed them mounted directly on brick walls.
Also, keep in mind, 50# isn’t all that heavy. I mean, do you think you could pull this wall over by hand? If you mounted a handle on it, would the wall come down if you hung from it? I’m not being sarcastic, if the wall is in bad shape or isn’t that strong, it wouldn’t be the worst idea to give it a fighting chance. Even an oversized piece of plywood with plenty of masonry screws to spread the load would help.
Another option; install 3/4" fire-rated plywood backer board against the wall, from floor to ceiling. It can support the hot water heater and also all of the connections to and from it.
As already discussed, this would address the potential problem. I think it would be very unusual to have an exterior wall built of a single thickness of brick, but if it’s some sort of infill panel (built in 1949 when buildings were flimsier than they were a few decades earlier), intended simply to provide a backing for stucco, it just might.
Ideally, you would figure out how thick the brick is. Anything thicker than a single brick thick would be more than adequate. But there are certainly situations where you’d have to drill into the brick to determine its thickness.
Finding common reference points on different levels of a masonry building to identify wall thicknesses can be very tricky. It was hundreds of years before architectural historians discovered that the cathedral of Chartres was built over a crypt of a very different design - columns don’t line up. But because the levels are only connected by enclosed spiral stairways, nobody took the time to run a geometrically accurate line down those stairs.
This would definitely be a permitted and inspected project. But I don’t know if that inspection would extend to the support wall (although I would expect it to)
The brick wall is regular brick, mortared but not pointed (that is, the mortar is not neatly finished, as this space was presumably not meant to be seen).
@Joey_P’s photo is pretty much what I had in mind for possible added structure. I’m going to ask the plumber/contractor about it.
Well, it turns out to be a moot point. The plumber also had second thoughts about hanging the boiler on that wall, although for other reasons, so he wants to build a simple floor stand out of angle iron (or something like that) and make it floor-mounted, like the current boiler is. I’m happy enough with that.
I got their estimate for the project today. Oof. It’s presented as a flat rate, but looking at the cost of the boiler, plus other parts of unknown cost, the cost for labor appears to be over $12K, and that’s considering that they will re-use most of the connections already in place, such as incoming gas and water, and outgoing hot water. Does anyone have experience to judge the reasonableness of this labor cost? The labor rate seems to work out to around $500 per hour, based on the estimated time (2-3 days) he told me we would be without hot water.
What kind of boiler? I assume it’s also doing your heat? I would definitely get competitive quotes. Depending on how many connections and venting can be re-used this could easily be a one-day job. More than $300/hr, even in SF, is pushing the envelope. In MT I’m paying $150/hr.
Is it possible to measure the thickness of this brick wall? A standard brick is 3" from front to back, and stucco would run about 1/4" to 1/2" thick. If the wall is much thicker, you may well have additional support within the wall. Even so, I wouldn’t be too concerned but if you want to spend the money, a structural engineer could advise you.
