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I’m replacing a small portion (4′ X 25′) of deck that cantilevers out from the side of a
home. The joists of the kitchen just extend out
4′ and I’ll be splicing new 2″X10″X12′ members
on to replace the exposed part. The original joists were southern pine and not pressure treated. Over the 30 year life of the home they have started to rot.
I’m wondering if I should replace them with pressure treated lumber or not. The deck is exterior and heavily shaded and so can stay
damp for long periods. So it is susceptible to
rot.
But they are not actually in ground contact
and I’m worried about dimensional stability
(e.g. a warped cantilevered joist could really
be nasty)
What’s the vote? The first joists lasted
30 years but I’d like to do the job right.
Replies
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tgordon, that nice, dry yellow pine is gonna rock and roll when that moisture settles in, so I wouldn't be worried about the comparative dimensional stability of the treated material
In today's world, I think the building inspector might have some problems with exposed, untreated pine structural material, so my vote is obviously to go with the treated stuff.
You may have to shave a bit off the height of the treated joists to slip them between the sill plate and subfloor.
Good luck, Steve
*tgordon,I gotta go with Steve....PT all the way. Put it in and retire....no rot.Ed. Williams
*I would use PT for two reasons. First, because of the shadey and damp exposure. Second, I would be concerned about insects entering the structure at this point. Check with your lumber supplier to see if kiln dried PT is available in your area. This is wood that has been kiln dried, treated, and then kiln dried again. It is more stable and takes finishes better than the regular PT. You pay a premium but in some cases it is money well spent. With surface protection, PT joists should last for 30 years or more. However, I would not expect the same lifespan out of treated decking materials that are exposed to sun and weather.
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I'm replacing a small portion (4' X 25') of deck that cantilevers out from the side of a
home. The joists of the kitchen just extend out
4' and I'll be splicing new 2"X10"X12' members
on to replace the exposed part. The original joists were southern pine and not pressure treated. Over the 30 year life of the home they have started to rot.
I'm wondering if I should replace them with pressure treated lumber or not. The deck is exterior and heavily shaded and so can stay
damp for long periods. So it is susceptible to
rot.
But they are not actually in ground contact
and I'm worried about dimensional stability
(e.g. a warped cantilevered joist could really
be nasty)
What's the vote? The first joists lasted
30 years but I'd like to do the job right.