I have a situation similar Larman's thread in this forum (evidently I'm not allowed to link to it here, sorry), although I have less room to work with. The house I'm working on has an attached 1-car garage that was converted to living space by a previous owner, details unknown. Upon pulling two layers of 1/2" untreated OSB subfloor, I discover a 2x4 PT joist system sitting directly on the slab, with faced fiberglass batts, paper side up, in the spaces. No plastic, hot mop or any other type of vapor barrier is visible. No idea what's under the concrete slab.
Still waiting on the local codes officer to interpret IRC and tell me if I need to ventilate under the subfloor or maintain a minimum clearance. Getting a skid in to dig out the floor is not an option (no more garage door of course).
I haven't torn into this situation real deep yet, so I can't even see how well the slab perimeter is insulated or sealed against the block & mortar foundation wall.
Reason for tearing into this was suspicion of mold after seeing some water damage near the floor on each side of an exterior door, and the floor had all kinds of peaks & valleys in it. Now that it's opened up, the floor actually looks quite dry, and with the exception of a little bit of black on the ends of the batts right up against the wall under the door, everything looks real dry & pretty. Inside the bottom of the walls on either side of the door is a different story, as a few critters & insects (fortunately no house eaters) decided to take up residence (eviction notice served). The 2x4s are not shimmed or cut to compensate for the slab uneveness, which explains the irregularities up top.
So I'd like to get a vapor/radon barrier down, and I'm thinking one of the best options is to apply a liquid waterproofing material like Sanitred (www-dot-sanitred-dot-com/basementfinish.htm again, too new to put an actual link, sorry) to the slab, even working it down around the slab perimeter to get it good & sealed. Then shim PT 2x4s to flat & level as a joist system, and insulate the cavities with rigid foam board. Replace the two layers of 1/2" with a single layer of 3/4" tongue & groove. Finished floor's gonna be laminate wood, so I'll float it on top of a vapor barrier underlayment.
If the codes officer comes back to say I can't have an unventilated joist system, then I either pour a second slab over the first, or how about this: pour some leveling compound down on the existing slab, then the waterproofing compound, then two layers of 2" rigid foam, followed by the subflooring?
Any ideas much appreciated. Need to get moving on this quickly.
Still waiting on the local codes officer to interpret IRC and tell me if I need to ventilate under the subfloor or maintain a minimum clearance. Getting a skid in to dig out the floor is not an option (no more garage door of course).
I haven't torn into this situation real deep yet, so I can't even see how well the slab perimeter is insulated or sealed against the block & mortar foundation wall.
Reason for tearing into this was suspicion of mold after seeing some water damage near the floor on each side of an exterior door, and the floor had all kinds of peaks & valleys in it. Now that it's opened up, the floor actually looks quite dry, and with the exception of a little bit of black on the ends of the batts right up against the wall under the door, everything looks real dry & pretty. Inside the bottom of the walls on either side of the door is a different story, as a few critters & insects (fortunately no house eaters) decided to take up residence (eviction notice served). The 2x4s are not shimmed or cut to compensate for the slab uneveness, which explains the irregularities up top.
So I'd like to get a vapor/radon barrier down, and I'm thinking one of the best options is to apply a liquid waterproofing material like Sanitred (www-dot-sanitred-dot-com/basementfinish.htm again, too new to put an actual link, sorry) to the slab, even working it down around the slab perimeter to get it good & sealed. Then shim PT 2x4s to flat & level as a joist system, and insulate the cavities with rigid foam board. Replace the two layers of 1/2" with a single layer of 3/4" tongue & groove. Finished floor's gonna be laminate wood, so I'll float it on top of a vapor barrier underlayment.
If the codes officer comes back to say I can't have an unventilated joist system, then I either pour a second slab over the first, or how about this: pour some leveling compound down on the existing slab, then the waterproofing compound, then two layers of 2" rigid foam, followed by the subflooring?
Any ideas much appreciated. Need to get moving on this quickly.