The old house has a plank floor with the expected cracks.I've tried different things in the past to seal cracks in plank floors.Haven't been satisified.Tried the sawdust and glue mixture,wood putty and most recently,butyl caulk. None held up over time.

So my idea is to forget abt the cracks, they aren't too bad.Wood was pretty dry when it was installed 100 years ago,so not as much gapping. Instead I'm thinking about insulating under the floor with the spray foam insulation (like Foam IT).I saw contracter size containers of it in the Building Supply shop.

That would give me both a vapor barrier and good insulation.And seal up cracks from below. House has a crawl space,tight to work in ,but doable. Will have to scare away copperheads ,probably,since we already had to chase one out of the house,but that's doable too.I'll send in Nick first! HA!

So what are the drawbacks? Would rodents chew it up? Will water spilled on the floor above get trapped and rot my boards,for instance? Not a big concern as that part of house will be the bedroom and living room,not a kitchen. But still would like to know.What abt. code? Would insulation have to be covered in this instance? That would be an issue.

So,what do you think? Any other options I haven't considered that I should? I really want to keep the plank floor as the floor.I love them.And I'm trying to keep as much of the house original as I can.

Thanks all.

-- Anonymous, April 23, 2001

Answers

We're in the process of (re)building, and are planning to insulate under our floors with sheets of Tuff R. It's not the normal application, but we have a bunch salvaged from the shack we tore down. We're cutting it into 14 1/2 inch strips to nail up between the joists. Sheets of styrofoam would be cheaper, but mice might chew it up. The spray foam might ooze through your cracks, and it's hard to apply it uniformly.

-- Anonymous, April 23, 2001

Hey Sharon, if you get that crawlspace insulated all warm and cozy you probably could hide a bunch more tomato plants down there! hehehe Sorry I can't be more help! :-)

-- Anonymous, April 23, 2001

Sharon: Sounds to me like it would work but I'd check into how far away you have to be for the foam applicator to spray on evenly. Also, about the oozing thru the cracks you'll likely encounter, if you still have the caulk between the planks it shouldn't pose a problem but if its gone maybe you could tape the joints to prevent that from happening. just a thot.

-- Anonymous, April 23, 2001

Sharon my construction experience would tell me that in the long haul foamboard of some type would not only provide far greater R value than spray on but be more cost effective and quicker to pay for itself.Best of luck.

-- Anonymous, April 24, 2001

Sharon, I havn't personally ever used the spray on insulation, except for the small cans which i've used for sealant around windows and doors, and to fill in around where pipes and wires pass through top plates, sole plates, etc. (by the way, don't ever use "normal" spray foam around vinyl windows, as it can bind up the window when it expands. There is a water based spray foam which works fine for this, though)

I do know that there are companies who specialize in spraying this type of foam. It's pretty expensive, but very effective.

As far as mice eating it, it's certainly a possibility, but mice are capable of eating almost any type of insulation, if given the opportunity. They'll even make nests in fiberglass, or haul fiberglass insulation out of a wall, ceiling, etc, to build a nice warm mouse bungalow somewhere else (like on top of my son's water heater)

If you have a serious mouse infestation, and start experiencing mousie damage to the sprayed on foam, you might consider putting a covering underneath the foam. This would be useless if the mousies have any other access to the insulation, though, needless to say.

Check out the price of this spray on stuff compared to polystyrene panels, which I suspect would be way cheapter and easier.

Don't worry about rotting out your floor boards by putting spray insulation under them, unless you spill water with great frequency. In fact, I would say that, generally speaking, the foam would help protect your wood. (Caution, though; my experience is in cooler climates, where the water vapor inside a house tends to condense when it hits cooler surfaces or materials inside walls, under floors, etc. I could only speculate about the situation in, say, Florida, New Orleans, Houston, or any other place with warm, humid climates.

As far as code, you'd have to check with your local building officials. Many, if not all, foam products can give off very toxic fumes when they burn. Under the floor seems like a less likely place to have a fire than in a wall or ceiling, but it could still happen.

JOJ

-- Anonymous, April 25, 2001

Thanks all of you for your thoughtful suggestions.I've used Tuff R before and that plus good caulking along each edge prob will work as well at keeping out the drafts, and be more cost effective. i don't remember what the big cans cost.

I had thought of it bc my brother used an outer covering of the stuff,applied by a company,over his fiberglass insulation, in his passive solar home.Best of both worlds senario. He was really pleased.

However,we live too far out in the boonies to find a company to spray,so I think I'll go with the Tuff R,instead.Glad I ran it past you all.

-- Anonymous, April 27, 2001

Sharon, another produuct which would be extremely easy to install if things are laid out right is reflectix. It is like bubble pak that has a reflective coating on both sides. It would be simple to staple up, is a vapor barrier and has an amazing insulting value considering it's thickness. Edges can be taped with foil tape giving a good tight seal. My floor beams are on 4 foot centers and we are considering using it on the areas of the house without carpet. If you go with the spray foam get some kind of breathing apparatus. Most of that type of product gives off some nasty fumes and in an enclosed crawl space... Good luck

-- Anonymous, April 29, 2001