crawl spaces

[sszakats]

I have 2 separate crawl spaces that open to my basement. The smaller space has styrofoam insulation along the outside masonry wall, but no insulation between the joists. The floor is dirt. There are no vents to the outside. How should this space be insulated?

The other large crawl space has a concrete slab floor, multiple vents to the outside, and insulation between the joists. The insulation is falling down because I think there are not enough metal push-in holders between the joists. I close the vents in winter and open them in summer. There is no styrofoam along the outside walls in this space. How should this space be insulated. The floors are cold in winter, and I am concerned about the plumbing down in this crawl space in winter. Should I vent some heat into this space? I was thinking of adding r13 plastic wrapped insulation to the existing paper-backed insulation to improve insulation as well as assist in helping keep the old stuff in place. Or should I staple up a plastic sheet to do this?

Thnks, STeve

[Wgoodrich]

YOu are required crawl space vents within 3 feet of the corners of you foundation wall. YOu are then required a minimum of 1 square feet of foundation vent for very 120 square feet of crawl space. This venting is used in the spring, summer and fall to limit moiture build up in that crawl space in wet weather.

When winter comes those vents are to be shut off making a crawl space of stagnant air. Stagnant air does not freeze water pipes as long as those water pipes are not exposed to convected cold by close proximaty to the foundation walls.

YOu sway back fiberglass insulation is a major reason but not the only reason that fiberglass insulation is not advised to be installed in floor joists. What is happening is that this fiberglass insulation during the spring and fall is obsorbing moisture in the crawl space like a sponge. When enough moiture is obsorbed into the insulataion it becomes heavy and even bisquine won't hold up that heavy insulation full of moisture.

Proper installation of a crawl space is to scrap back as much of the pea gravel as you can back to dirt. Then in the lowes point of the crawl floor if water tends to stand in the crawl install a sump hole bucket. Then buy a roll of bisquine wide as possible and spread that bixquine across the crawl space dirt floor. Then install the pea gravel over the bisquine to hold it in place.

Moisture is in the earth, as the freeze works out of the earth the moisture rises. The bixquine on the ground is a vapor barrier to keep that atomized moisture from sifting up into the crawl space.

Without the bixquine and if you hang fiberglass between the floor joists you should now see how you have a sponge in a moisture rise condition. That fiber glass would not stay up in most occasions.

If you want to properly prepare your crawl do the bisquine thing then use blue board cut to fit tight between the dirt and the bottom of the floor joists fit tight to the crawl space foundation block. No need to glue to the block just fit the blue board tight to the dirt and floor joist then scoop dirt piled up a bit at the bottom to as a bridge holding the blue board in place. Then cut some fiberglass insulation with paper backing as a vapor seal and stuff that insulation between the floor joists againgst the outside band board. Do not insulate the vents from the inside. Cut blue board to fit tight and install that piece of blue board to seal the foundation vents from the outside late fall and remove that blue board from the foundation vents in the spring and store these peices of blue board inside your cawl entrance for next fall to use again.

You have then sealed your crawl space for dead air space keeping your water pipes from freezing and making your floors warm due to the minor heat loss of heat pipes and hot water lines in the crawl space in a static air containment area. Try it you will like it.

If you want to save on hot water heater cost use foam pipe insulation on the hot water lines. There will still be enough heat loss into the crawl space to make your floor more warm yet save you money on keeping your hot water hot longer.

If you are pouring a concrete basement floor then use bizquine on the dirt then blue board laid over the bisquine then pea gravel or pit run as fill over that and pour your concrete floor. YOu would be surprised the difference of dryness in your basement if this is done as you pour your basement floors.


Hope this helps

Wg

[sszakats]

The larger of my 2 crawl spaces (and the one where all the insulation is falling down) has a concrete floor. Should it be insulated differently from one with a dirt floor?

Thanks, Steve

[Wgoodrich]

Concrete crawl space, boy I'll bet that would be hard on the kneecaps? Ha Ha.

In the case of a concrete crawl space I would install the blue board on the foundation walls and hte fiberglass insulation stuffed sealing between each floor joist against the outside band board excepting the vents. I believe you mentioned one area that did not have foundation vents. If this is true you should keep an eye on that crawl space for mold and mildew that can cause rot of you framing members and / or health hazards due ot the mold making people sick. Often times mold will appear in a non vented structure due to lack of ventilation. Be causious of this non vented crawl area. Watch for moisture that is likely to build up in that non vented crawl especially in late spring or early fall. If you have vents in the foundation wall or band board then do not seal those off except in the winter and only plugged on the outside so you remember to remove those blue board vent blocks from the outside of your vents in the spring.

At this point all we can hope for is that the vapor barrier was installed before the crawl space concrete floor was installed. If you find build up of moisture in that crawl in the winter with the vents closed then you can still lay bixquine down on the concrete floor and then lay blue board or cyletex [fiber board] on top of that bisquine to hold it in place and cushion the floor saving your knees.

Just my suggestion best action of partial committed condition.

Hope this helps

Wg