An electrician drilled a one-inch diameter hole in my house's rim joist while adding a new circuit. A half inch hole is sufficient to pull the romex through but a larger hole is more convenient for him to insert a conduit fitting into the sheet rock at the end of the hole.
Would this one inch hole significantly weaken the rim joist? Should I fill it with epoxy or something?
There is a simple rule to apply when drilling in joists. Generally, drill holes with a diameter of no more than one-third the depth of the joist, staying 2 in. away from the top and bottom if it's a dimensional lumber joist. Therefore, if you have a 2 x 12 joist, your max is 3 3/4" hole. The 1" hole is fine as long as it's not within the 2" from top or bottom.
If you have manufactured I-joists, you can drill holes up to 1-1/2 in. diameter almost anywhere in the web area (the area between the flanges). Just stay 6 in. away from any end or load-bearing wall.
No to the first question. To the second, caulk would be a good idea to keep out weather or little critters
What would you say if he drilled a 4-1/4" hole for a dryer vent?
Hi Bob,
A one inch hole will not be a problem.
There are rules how big holes and notches can be in normal floor joists, based on the size of the joist and where the hole is placed. This is to ensure the joist is not weakened for carrying a load across a span.
However, a rim joist is generally supported along it's entire length, either by the foundation/sill or the first floor walls below. Unless you have a large point load, like a bearing post directly above, you can make just about any size hole in the rim joist.
Of course, structure is good, so minimize holes and notches when possible.
If there is more than 1/4" space in the hole, I would probably shoot in some expanding foam, or push in a bit of foam backer rod (available at any home center in many sizes). Then seal the exterior opening with a good quality polyurethane caulk (exterior rated).
Of course, for a single small hole like this, caulk alone would probably be all you need.
Anthony Watson
You're probably ok as long as the electrician got a permit and had the structural modification inspected.
If you do, make sure you get a permit and have the work inspected.
You have to be kidding about a permit and structural modification inspection!
If you're humor impaired, may I suggest reading the entire thread to relieve any confusion?
If you can't run with the big dogs, stay up on the porch!
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