Expert: Michael J. Owen Date: 7/8/2008 Subject: Attic Ventilating and Insulating
Question I am a transplant to Central Texas and my wife and I bought a fixer upper Ranch House with an difficient attic space -- poor insulation, improper ventilation and exhausting. I have been reading "Stans" comments on your website and find them very informative.
My project is in high gear now. I want to blow insulation (which I'll get back to in a moment) but am trying to address the ventilation/attic in/out issues first. This house has no ridge vent or gable vents. Prevailing wind would strike the end of the house where a gable vent COULD be but turns out that the end is all Brick and hence, no vent. IN air is only achieved at the soffets. Soffets vents were about every 4 ft and were about 2 1/2 inch round holes that I increased to 4 x 9 rectangles. Also added a second Turbine vent on the roof (have a 12in and a 14in now). And am trying to Mentally adhere to Stan's 150 X 1ft attic floor space to incoming air ratio.
Now the Blowing queston...
I do not wish to obstruct my soffet vents when blowing insulation. The pitch on this roof is very low and from up top, I will be lucky if I can even get to the soffet openings from the inside to baffle these. My plan is to blow 18 or more inches of Cellulose and near the soffets...from the inside that will be only 8 or so inches near the soffets.
Please provide your thoughts on doing this correctly.
Best Wishes, Eric in Central Texas.
Answer Hi Eric. Regarding your first paragraph, you may find the web site enclosed helpful.
Considering the other question about blowing insulation in and bearing in mind you have limited space to work around the outside, how about using rolled R.19 or R.30 for the first few feet. This could be pushed into place with a stick. Polystyrene baffles could then be slid into position from the attic and some sort of temporary shield to stop the blown insulation getting into the space. Perhaps you could use plastic sheeting and staple it to the rafters and ceiling joists and then remove it after blowing. Hope this helps and maybe someone else may have a better suggestion. http://www.gaf.com/Content/GAF/RES1/ROOF/RS_whyuse_ventchart.html
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