Sister #2's house in Northern New Jersey. Partially sheetrocked/finished already. Boiler and hotwater piping located there. No existing inulation/sealing. 2 sumps. 6 foot high water mark. Suggestions? Thanks.

Concrete block foundation. Foam the blocks? Boiler replacement within a week. Relocate?

I will wait for Dana to chime in but I would suspect that a moisture proof rigid foam across the block wall would be ideal followed by the stud wall with an unfaced FG batt or cellulose.

Cellulose or FG? In a flood zone? Maybe in the ceiling.

Fill the blocks with tripolymer?

Are you going to be drywallling the space?

Are you worried about capillary moisture through the block or bulk moisture?

The center 1/3 of the space is recently drywalled(unfortunately). I am worried about all moisture.

Although I don't see a problem with eps on the walls I'd rather not put anymore sheetrock down there. Got any suggestions Dana? Is covering sump pits to reduce humidity levels recommended? How about using a Heat pump dhw to reduce humidity? Lots of questions. Thanks

Check with the code. Fiber faced iso might be acceptable per ignition/thermal barrier.

An inch or two of unfaced EPS (mastic-sealed seams) trapped to the CMU wall with a in interior studwall, with unfaced R11 batts has some drying capacity, but with a high water mark at 6' you'd still have to replace the studs after the next flood if they take a real soaking. Cellulose should never be used in a basement that floods- it would take years to dry.

Going with 3-4" of unfaced EPS (R12-R16) held in place with 1x horizontal furring, (or metal channel furring for low flood susceptibility) through-screwed every to the CMU with tapcons, onto which the interior finish wall hangs is probably the best solution on the insulation end. Iso would take on moisture during a flood and retain it, whereas EPS takes on ~5-7% moisture by volume in the first week losing ~10% of R value while-wet, but gives it all back withing a few months after the water recedes. EPS is used as permanent flotation in marine environments due to it's excellent saturation resistance. (Don't use Z-furring often used with foam insulation in commercial construction that cuts through the foam layer, as it's too much of a thermal bridge, cutting the effective-R by nearly half.)

I'm not sure if there's any common building materials that would cut it in a true flood condition except fiber-cement board. MGO board is pretty good, but it comes with it's own set of issues. Fiber cement board with a hard-plaster finish interior might cut it in a flood, but I dunno...

Covering the sump pits doesn't change the humidity issue a whole lot, but it might save you from a broken leg. ;-) In NJ, other than massive bulk water intrusions, it's AIR infiltration during the summer that raises the RH to mold inducing levels. Using 1-2" of closed cell foam to air-seal the band joist & sill on to the interior EPS should go a long way toward sealing the less-visible (but often quite large) air leaks, after which a 65-70 pint dehumidfier draining into one of the sumps would handle what humidity load that's left pretty efficiently. As long as it stays below 60% RH the mold hazard is quite low.

Are there spray foams that don't require thermal barriers?

Dana,

Any issue with using 0.5lb open cell foam at the bands in a thicker depth? It is still and air barrier but has a bit higher perm rating than closed at that point so can dry to inside.

Getting the air stopped is going to eliminate most of the RH that is creating the issue carried on bulk air movement.

There are some fire rated foams but the ultimate interpretation is up to the code official.

In zone 4 you can use half pound foam at 5.5" at the band joists and you'd be fine. In zone 5 not so much unless the exterior siding has a vented rain screen gap (or it's vinyl siding, and inherently back vented). Otherwise the more vapor open foams can lead to high moisture content in the band joists at the end of the winter due to vapor-diffusion alone. Northern NJ is the cold edge of 4, the warm edge of 5, so you might be OK. Look at Demilec's 0.7lb foam- it's somewhat lower-perm than half-pound foam, and higher R. Alternatively 3" of the more vapor open 2lb Icycnene comes in at about 1.3 perms & R15. (But is more expensive than R15 of 0.7lb Demilec or generic half-pound foams.)

I'm not aware of fire-rated polyurethane spray foams. Cemetitious foams are fire rated though.

There are very few fire-rated rigid foams, and those are only foil-faced iso products and are not suitable for use below the high-water mark.

I agree with concrete/eps and then concrete/hardi/stucco for a flood proof insulated wall. You can use blocks, SCIPs, tilt-up or poured walls to get this.

Posted By Dana1 on 23 Nov 2011 02:41 PM
In zone 4 you can use half pound foam at 5.5" at the band joists and you'd be fine. In zone 5 not so much unless the exterior siding has a vented rain screen gap (or it's vinyl siding, and inherently back vented). Otherwise the more vapor open foams can lead to high moisture content in the band joists at the end of the winter due to vapor-diffusion alone. Northern NJ is the cold edge of 4, the warm edge of 5, so you might be OK. Look at Demilec's 0.7lb foam- it's somewhat lower-perm than half-pound foam, and higher R. Alternatively 3" of the more vapor open 2lb Icycnene comes in at about 1.3 perms & R15. (But is more expensive than R15 of 0.7lb Demilec or generic half-pound foams.)

I'm not aware of fire-rated polyurethane spray foams. Cemetitious foams are fire rated though.

There are very few fire-rated rigid foams, and those are only foil-faced iso products and are not suitable for use below the high-water mark.

Dana,

Does the ASTM E84 test not qualify a foam for being fire rated?  I don't see where it is class a, b, or c rated.

http://tigerfoam.com/

As far as vapor diffusion goes, what is the perm rating on 5" of 0.5lb foam at that point.  Obviously there is no air bulk air transfer and that is going to negate much of the moisture movement potential.

Happy Thanksgiving everybody!!

If the power stays on, you can design for pumps to keep the interior dry even with water surrounding the house. Ie, a concrete boat.

Of course the power doesn't stay on during the big ones(3 in 20 years). Why would it be that easy? What's a SCIP? I'm thinking for practical purposes an inch or two of eps on the flat areas, closed cell on the sills and "busy" walls. Then cover with 6 inch batts. The batts may pass for fire barrier. Replace batts as needed do to flooding. Is this wishful thinking? Happy Turkey

I'm not sure if the ASTM E84 levels on flame spread & smoke for Tiger makes it for being able to skip the ignition barrier requirements of the building code- it basically means it's won't flash on you like a can of gasoline. SPF installed by pros have varying ASTM E 84 ratings, but SFAIK all still require ignition barriers.

On jobs that are 1000 board feet or more, using the DIY foam kits is going to be more expensive, and is more likely to have problems than simply letting the pros do it with their experienced installers and temperature controlled spraying equipment. If you're only doing the band joist and foundation sill on a small house sometimes a kit makes sense, but with a whole basement wall, not so much.

At 5" most half-pound foams are ~10 perms. Demilec's 0.7lb goods are about 5 perms @ 5.0" (I looked it up.) Half pound Icynene (LD-C-50) is 11 perms @ 5.5". For the band-joist to be safe in zone-5 you need it to be around or under 1 perm, (and not more than 2.)

See: http://www.demilecusa.com/wp-content/uploads/2011/10/TDS-Sealection-Agribalance.pdf and, http://www.icynene.com/assets/documents/pdfs/Products/ICYNENE-LD-C-50-Specification-Sheets-US.pdf ) Icynene's MD-R-200 high-perm mid density product is 1.3 perms @ 3", which is about the same as 1" of XPS.

Understand the difference between air-barrier and vapor retardency: Vapor retarders limit the amount of water vapor that gets through based on the difference in VAPOR pressure (related to the of the humidity content of the air) on both sides of the material, whether it's air-tight or not. An air barrier can be both air tight (under differences in AIR pressure) and vapor-open, which is would describe most half-pound spray foam. At 10+ perms it's essentially vapor open- quite a bit of moisture will pass, which is both good and bad depending on where it is in the stackup and climate. In US zone 5 it's too vapor open for the band joist, but would still be fine on a CMU or concrete basement wall, since the CMU & concrete can handle the seasonal moisture, whereas wood cannot. While most moisture problems in above grade wall are caused by bulk water (poor flashing) or air-leaks, not vapor diffusion, without ample drying capacity toward the exterior, vapor diffusion through half-pound foam on the band joists could lead to rot issues.

Dana,

Do people ever see any rot at bands behind the fiberglass ever? I am assuming no in this case because the FG allows for so much air movement and therefore keeps the band above dew-point.

Is the concern with the open cell that in a climate like zone 5 or above that it will allow too much diffusion, hit the cold band, condense, and foster rot? Obviously the bulk moisture needs to be managed from the exterior because the application of a CC foam is going to eliminate any drying to the interior in this case.

What would be the minimum required thickness of CC to avoid condensation on the interior surface of foam and get to the 1-2 (or below) perm rating? I am guessing about 2" yielding about an R-12. If you wanted more in the wall at that location, could you then apply the cheaper open cell foam or does and R-12 not give you the proper resistance to dew point surface temperature at the close cell/open cell connection?