1900-ish brick-over-fieldstone foundation seems perfectly happy right now, but [digression about fieldstone aside]... What's best practice? What do I look for to tell when maint is required?

(Standard grumble about houses not coming with inspection/maintenance manuals...)

  • 1
    Just my personal opinion, but I'd never finish a fieldstone foundation. For one reason, like you say, it needs to be inspected. The other is that they definitely let water in. – DA01 Sep 11 '15 at 20:53
  • The fieldstone isn't where I get infiltration. My problem areas are one of the joints between that and the new concrete foundation, and the bulkhead door. But that's another question, I think. – keshlam Sep 11 '15 at 21:32
  • 1
    Well, FWIW, houses with fieldstone basements that I've seen that have been finished have essentially built a new wall 2' inside the current foundation. They then leave that gap behind the new wall and the foundation to access for future inspection/maintenance. The problem with this is that a) that eats up a lot of room and b) it creates a rather humid space that you need to work to keep dry. – DA01 Sep 11 '15 at 21:47
  • Probably true. Still leaves the original question of what to watch for when though. – keshlam Sep 11 '15 at 23:49
  • 1
    Oh! Yes, the original question, well you know you need to tuck point when the mortar starts falling out and crumbles with your fingers. There's obviously no way to know that's needed unless you have access to the interior side of the wall. – DA01 Sep 11 '15 at 23:59

How do I know if/when tuckpointing is necessary

You need to tuckpoint when the existing mortar is failing. That could be that it's water damaged, cracked, or just getting weak. To see if it's weak, take your key and drag it along a joint...if it's easily flaking off and scratched...or worse, crumbling, then it's time to chisel out the damaged mortar and tuckpoint.

especially if I finish the basement?

Well, that's the catch. You can't tell if you need to tuckpoint your joints unless you can see the joints. So you can't exactly just finish the exterior wall and assume you're good to go. New joints should last a long time, but they will eventually fail due to the inevitable moisture movement that happens in a fieldstone wall.

As such, you probably don't want to finish the exterior walls. I'd argue you shouldn't finish a fieldstone basement at all, but I've seen it done where they build a floating wall 2' or so inside the exterior wall. This gives you a walkway around the perimeter to keep an eye on things.

| improve this answer | |
  • 1
    Actually, the original part my foundation is mostly brick, with a fieldstone footing. But it sounds like your answer holds for any mortared foundation, so unless I want to do something drastic like jacking the house up and pouring a concrete foundation under it, it sounds like the answer to that part is either only finish the extension's (poured-concrete) basement, or figure out how to finish the old section with removable panels so it can all be accessed for service. – keshlam Sep 13 '15 at 2:44
  • @keshlam did you end up doing any basement finishing? – glenviewjeff Aug 19 '16 at 17:27
  • 1
    @glenviewjeff: Not yet. Current plan is to do the new half fairly soon, but I'm still not sure what best answer is over the brick foundation. See also my other q. about how hard I want to work to waterproof that, vs. ending the insulation an inch or two up and accepting the risk of a damp floor. – keshlam Aug 19 '16 at 18:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.