floor joists?

[diamond]

Would it be better to use pressure treated floor joists OR regular un-treated wood? I live in East Tennessee and am not sure if this would be worth the extre cost. Don [img]/forums/images/icons/confused.gif[/img]

[Inspector507]

diamond,
I have no idea if cost is an option, but look into steel floor joists. They are getting very popular here in Ohio. Not sure if even formosa termites can chew through these things. They're more stable than any wood floor joist system. Quieter too.
Dietrich Steel Floor Joists

[rlk]

Diamond, what is the reason for using pressure treated joists? If you are worried about termites, then you also need to be concerned about the plywood subfloor, the wall studs, and even the paper on the sheetrock.

Rather than spend the extra dollars on pressure treated joists, I would use regular joists; have a reliable company treat the foundation/crawlspace for termites; then take the money you saved and put it into insulation.

If you are not concerned about termites, then clue us in as to why the question about using pressure treated joists.

Bob

[AndyF]

Pressure treating only provides a benefit if the wood will be in pretty regular contact with moisture. Pressure treated wood is often used for sill plates, but typically doesn't provide any benefits as a floor joist. A downside to using pressure treated wood for joists is that it is usually wet when you buy it and is much more likely to twist/warp/shrink than an untreated piece of 2X lumber.

[Handyman]

Hey Diamond... I just built a house here in central Tenn.

After your block is laid, you put down a termite sheild which is pretty much nothing more than a strip of black plastic the width of the block followed by the sill which is your 2x8 PT board that is secured to the block then your floor joist lays on top of that. No where does the floor joist make contact with the concrete. In fact only PT should make contact with any cement.

Termites was my main concerned also and what I was told by the termite man was that they need moisture to be able to travel like a mud tunnel, foam insulation against the block, something that traps moisture allowing free moist travel for the little bugs. In stead of insulating the the outside wall, I insulated the flooring and installed my pipes (also insulated) between the floor decking and the insultation (R 19 )

My highest bill last winter was $125 with a 12 seer heat pump and my average bill during the summer was $40

[gsganzer]

I don't think I'd use PT for the joists. As stated earlier, they are too wet and shrink, twist, warp when drying. I'd use regular lumber for the joists and PT for the sill plate. They also make a narrow mesh screen that goes between the sill plate and the concrete wall, this way you avoid wood to concrete contact and allow the sill plate to remain dry. I think I've also seen a thin closed cell foam material for the same purpose.

One thing to note, make sure they lay down a vapor barrier on the ground of the crawl space and lap it up the walls a little. Typically they'll pour the curtain walls and then grade the crawl space. Then they'll put down heavy mil plastic sheeting and cover it with some sand or pea gravel to keep it in place. I could kill the guy who built my house 35 years ago for not doing this. My North Texas clay is like a sponge. I've installed gutters, graded away from the house etc. My crawl space still gets damp in the wet seasons. I replaced 90 feet of rotted sill and 36 floor joists before I bought my home but the dampness is like a cancer for your flooring and sub-structure.

One of these days, when I'm properly motivated, I'll crawl around under the house and roll out some plastic. This will be a chore, my crawl space is only 18". Two places I detest working, attics and crawl spaces. I have enough bumps on my noggin already.

[fivestring]

<font color="blue">" My North Texas clay is like a sponge. I've installed gutters, graded away from the house etc. My crawl space still gets damp in the wet seasons. I replaced 90 feet of rotted sill and 36 floor joists before I bought my home but the dampness is like a cancer for your flooring and sub-structure." </font color>

Did you all get our NC clay??? [img]/forums/images/icons/grin.gif[/img]

We used to close the foundation vents about this time of year and open them in April, but now I've been advised to keep them open year 'round for ventilation. It seems the "sponge clay" holds the humidity year 'round and with the vents closed, the humidity has no where to go.
Do you close your foundation vents in the winter?

[gsganzer]

I used to close the vents, but the last few years I've been leaving them open. That clay soil's a curse.

[Pat]

18 inch crawl space?????????? I'm not claustrophobic but I'm also not small or thin. ****... I don't have that much fun under my mom's house with a 24 inch crawl space but I'll quit complaining about it (would you believe, cut back a little, at least.)

I have it partially covered with plastic under there and I have several automatic vents in the stem walls. They open when it is warm and close when it is cold and are somewhere in between when it is somewhere in between. They are plastic and metal construction, have anti-bug and rodent screens, and cost about $9 each at Lowe's. Even in winter, the ones on the south side and the west end open up when the sun shines on them if it isn't too cold and windy.

The subterranean termites typically build tunnels out of mud to cross the stem wall while climbing up to the wood. Regular inspection and busting these tunnels will stop them. If you see tunnels then contact a termite company.

I placed galvanized flashing between the sills and the stem walls and bent the portion sticking out into space under the house, down at an angle. I was told they won't tunnel down and around the sharp edge (making a 180 degree "U" turn) to get to the wood. I also used flashing on top of all piers so they couldn't eat into the wood bridging between the tops of the piers and the floor joists/beams.

As far as termites go, the meek will have to get in line behind them as I think termites (and roaches) will inherit the earth.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]