Prepping Basement Rimjoist for Spray Foam Job
loya1ty
| Posted in Construction Techniques on
I’m having a company come in December to do a crawl space encap, and have also hired them to spray foam the basement rimjoist perimeter. I’d like to spend the next month doing as much ‘prep’ work as I can do have the best installation now and the easiest convenience later for when I finish my basement.
What are some tips out there for dealing with plumbing and electrical that may be nested in the joist bays? Do I just accept that when I re-wire for the basement that I will just need to cut and leave buried old lines and run the new ones along the newly framed walls? And the same for piping? Thanks.
Replies
Planning ahead is always a good thing.
Wiring in the bays along the rim joist should only be headed upstairs. No reason to have to disturb these after they are foamed.
but if you have reason to, not a bad idea to run some new wiring before the foam is placed. New basement walls really call for a new circuit or two from the service panel.
Review codes on holes in joists before getting the drill out.
Any plumbing you would have to dig into, similarly would be good to do now.
You also will want to clean out those bays to get rid of as much trash (grit, dirt, sawdust, empty pop bottles....) as you can which may have been there since the house was built.
Thanks for the tips. A new panel and circuit runs are something in the future so I might just accept them getting cut/buried in the foamed bays, and have all new wire for upstairs circuits ran through conduit or other means. I'm not worried about basement circuitry runs.
The plumbing though... yeah that's another story. Maybe some temp pex/sharkbite connections to get the plumbing out of the bays, and then tackle larger pex runs later once i get to re-running pex from a manifold? I'm pretty much trying to retrofit the most new building science techniques i can into a 'custom' 70s colonial lol
Based on the experience spray-foaming my roof and having issues later: 2 things that can lead to problems with adhesion are cold temperatures and surfaces that aren't clean.
Don't know how cold it gets where you are in december but I'd ask them about that. If you're in Michigan and they say "never had a problem", I'd be suspicious. They might just have you turn up the heat in the basement they day before they come but it might be better to do it later in the spring.
Cleaning up the place like Mike said is a great idea. Don't know how old your house is or what kind of shape the wood is in but maybe clean it up with sand paper? The guy that did mine told me (after we had failures, of course) that putting a primer on beforehand can help. Again, ask your contractor.
It's possible rim joist foaming doesn't have the same challenges as rafters and roof deck and this is all overkill but if you want to be cautious, those are some ideas for you.
Those are good points. I've cleaned them up already when I removed the old fiberglass batts, and i think the rim joist bays will be a better structure not having to fight gravity. I'll certainly repair a few spots though that have some previous damage from older doors above just to ensure a nice surface rather than covering up crap.