When the insulators did my new house. The basement was done as follows: any framed pony walls were insulated, followed by VB. where 2×10 joists met up with a ledger rim joist made of PT 2×10 which sat in foundation concrete corbel, they simply ran the VB and accoustical sealant.
This didn’t look right to me as VB should noramlly be placed on the warm side of insulation.
At this point the basement is unfinished, but will be finished shortly.
when I had my framing inspection I passed. I raised the issue with the inspector, he sort of hemmed and hawed and then said it was “ok” followed by “you’ve got pressure treated there.” ( which is true, but I’ve also got non PT pressure blocks for all my joists which are also wrapped in the VB.)
What I feel I should be doing is rip out the VB, place insulation in the joist bays then redo the VB.
any thoughts….
Replies
Best time to get a response is in the evening.
But you might want to clarify the construction.
What I am familar with is that the a mudsill is laid flat on the top fo the foundation. Joist are put on top of the mud sill and the rim joist has the narrow edge vertical and covered with the finished siding.
The mud sill is rot resistant (PT) because it is against the concrete. However, rim joist is not.
And what is your climate and insulation.
Yes night and weekends are best time for multiple responses.
when you ask me to clarify the construction. do you mean as in "new" construction. yes it is. or are you looking for specifics to the construction details?
The detail you outline is your basic foundation detail; which is incorporated into the details of my foundation. However, I also have steps in my foundation as well as several area where it is desired to have the foundation wall higher to accommodate the exterior finish grades better. Therefore the PT rim joist is actually set in a ledge of the foundation (or "corbel") . This detail is similar to when a foundation wall is formed to have a "ledge" on the outside of the foundation , when one plans to have a rock or stone veneer.
Therefore, I have the detail that you describe, the one I just described, as well as pony or "crib" walls.
it is the corbel detail which is the the detail I am concerned about.
.....oh yeah, my climate is wet, and insulation is batt
Edited 3/31/2006 1:23 pm ET by alrightythen
bump
I find your descriptions rather confusing too. How about a pic?
From what I can decipher, it sounds like the pony walls are all good?: >> The basement was done as follows: any framed pony walls were insulated, followed by VB. <<
Your real concern is that the joist ends and rim board were not insulated at all, and only a VB was installed? : >> where 2x10 joists met up with a ledger rim joist made of PT 2x10 which sat in foundation concrete corbel, they simply ran the VB and accoustical sealant.<< Normally, in a heating climate, the insulation would be installed with a VB on the living space side. Is there some kind of insulation (ie rigid foam?) on the outside or elsewhere within the foundation assembly? If not, it sounds like you do need to remove the VB from the joist ends, install insulation in the joist ends, and reinstall VB. On the other hand I live about 500 miles south and 2000 miles east of you.
The 2nd floor floor system (if there is a 2nd floor) joist ends would be insulated the same.
Does your framing inspection include a insulation inspection? Here, you get the framing inspection, and then the insulation inspection is later, I guess the thought being that a building inspector can'r really see the framing if the insulation is already installed.
I gather it's a poured concrete basement foundation? Not really related to your Q, but that sounds like kind of an unusual detail for the first floor system to be supported by an interior ledge around the foundation unless these basement walls are being used to support a brick/stone/etc veneer above? Around here the corbels or brick ledges are installed on the outside of the house and just below grade.
I've got no way to get pics on. or I would have....pics worth 1000 words they say or at least the 100 or so that I had to use..lol
anyway Matt, you nailed it. while, the method that Bill described is the most common method for foundation/ 1st floor construction and I would say is pretty much incorporated into most or all building designs ( as in mine)
The corbel detail is quite common for many houses. But probably only in certain areas and with certain house designs. I would have to say that at least 75% of the houses I have framed have had a corbel design. mostly though, ones I have worked on in the past we have bolted on microlam rim joists (used in conjunction with TJI's) onto the foundation wall with building paper sandwiched between rim and concrete. A 2x3 plate then sits in the corbel at same height as top of ledger with the sub floor extending onto the plate. This allows the foundation wall to extend higher to accommodate the higher grade on a particular side of the house.
If one frames or builds houses on pretty much level sites you will probably never see a detail like this. most of my framing has been on the hills and mountain side of North and West Vancouver here in B.C.
yes the second floor is done correctly as is the mud sill and pony wall areas of the foundation.
also, yes there was a framing inspection followed by insulation inspection prior to drywall.
and yes our brick ledges are done on the outside as well, which makes sense 'cuz that's where the brick or stone is.
being 500 miles south and 2000 miles east of me you got everything pretty much bang on, and I will be redoing the VB with some insulation put in, since you seem to concur with what I thought.
I think that part of the problem is calling it a corbel.In my mind a corbel is individual brackets that jut out every so often.Instead you have a ledge, just like a brick ledge.What is on the out side of the house at this level? Is under ground? and is it water/damp proofed? Exposed? Or Covered with finished siding?My house does have true corbels on the foundation. They are on the outside and support an elevated walkway in to the top level of my house.My house is on a hillside an oneside of the foundation is at grade on the front and on the back 12ft high (against the garage and basement under it). I don't remember, but I think that it was done with just a framed wall next to the foundation. However the house is in a T with the top being the house and the stem the garage. And the house is 3ft wider on each side than the garage. So outside the 12ft walls there are 4ft walls that wrap 1/2 around the sides. And there are poney walls on top of them.In fact I just made a quick measurement from a window on the isndie and out it seens that the back wall is 12" thick.
I agree with you on the true definition of the term corbel. While I have never looked it up, what you describe is what I understand the origin of corbel to be. At the same time, when I learned this technic, this is what it was called, and since then others such as delvelopers and inspectors I have met have used and understood the use of the term in these situations the same as I have.
But essentially yes it is a ledge.
the outside of the foundation is backfill. And the foundation is waterproofed. which is the reason the foundation is designed this way. if the exterior grade was such that siding could exist, then I'd be using a mudsill.