Insulation and ventilation questions..
Hi,
I’ve been a subscriber for 20 something years. I have that many back issues on my bookshelf : loved it and still do. <!—-><!—-><!—->
A couple of months ago, I read an article that seemed to suggest that in the case of an older house, it might be a better tact to seal against air flow, than to try to provide optimum ventilation by heroic means. Just install power vents in the wet areas – that baths and kitchen. Then just seal everything else up; blow foam into the sill and rim joist areas, and between the rafters from ridge to sill.
I have such a challenge of a home, about 70 or more years old. Seven hundred or so square foot ranch with a 6 ft. “head knocker basement”. My wife, daughters and I live in it. We are currently presented with the unfortunately untimely opportunity to : 1.) replace the roof, is a cold roof better ? I have had ridge vents installed and some of those “cans”, but no soffit vents. Someone once told me there is a product out there that mounts behind the gutters, that draws in air underneath, acting as a soffit vent. Anyone have experience with it ? My gutters actually come off and on fairly easily – has the nice hangars, not spikes. Even if this is viable, I still wonder about the conclusions of that article (forget venting), and wonder what’s best.
When we first moved into this place one of the first things I did was to install vent fans in the bath and kitchen. Unfortunately, I was ill advised and paid a co. to blow in “foam” insulation into the outside walls. I never saw the product itself till recently, when a shower wall finally presented a leak behind the tile walls and I am now tearing everything out to the studs. When I got the rock lath off the wall, it was soaked as you can imagine, all the way to the exterior sheathing. The “foam” insulation, even where it wasn’t wet had shrunk and had large voids. It crumbled into white dusty flour when you touched it. The wet stuff was like “white flour gravy.” In the bath, I’ll either hire to blow in foam or try some fixes suggested for “gonegolfin”, glueing rigid foam with great stuff. Don’t have a clue what to do with the rest of house. All that “insulation” is probably just as bad with large voids, etc. <!—-> <!—->
What are the optimal fixes ? The economy is real bad – it must be cost effective, short term and long – most importantly. Please share your thoughts.
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Replies
I have similar problems with foam insulation. That is why I do not recomend foam to anyone. There is to much left up to the operator on site. I am curious about the responses you will get. My plan is to remove from the outside and reside the whole house.
In college I installed a foam insultion ... as a job. That and subsequent learning ... foam sprayed/installed on site is heavily dependent on the right mix of the foaming ingredients ... maybe this isn't as critical w/ new products, but the concept really isn't any different, in some respects. You mix two materials that expand and fill a cavity. The ratio of the mix, I think, will be the critical element.
Sounds like you have reason to believe there is a foaming problem. Don't forget, though if you have moisture problems in the bath, that ventilation is critical to proper bathroom performance. This is particularly true w/ the fact that insulation/foam was added to the existing construction. Areas that generate moisture require control of that moisture (exhaust fans). As you insulated, the natural breathing of the house decreases. Unless you increase the control of mechanical ventilation, you may end up w/ a problem. Older houses often simply relied on the wind and natural air leakage of the house to disipate moisture. Even badly installed foam will tend to decrease this natural ventilation.
Attic ventilation is important in many locations ... particularly cold and humid areas (e.g. upper midwest). That is why the building codes require minimum ventilation criteria (both at eave level and at ridge level).
You have several issue going on ... IMO you need to address each in formulating a solution that will serve you well in the long term. Consider each issue carefully and develop a game plan/solution that will work. Leaving one item unaccounted for may mean you end up w/ problems down the road.