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Scott Plantier
Posted: Aug 14, 2007 12:26 AM
.5lb attic job questions
Hi,

I have an attic spray of .5lb soon and have a few questions for the experts here at this forum:

1. Being a hip roof means some of the bays are "blind" with access being only through the plaster/lath slopes of the 2nd floor rooms or through the shingles. Should I rotozip the plaster for their access or is it considered the sprayers job? It wasn't brought up by me who ASSUMED it was the sprayers work.

2. What's accepted practice for the multiple chimneys found in these old white elephants we call homes in New England? Nothing mentioned by the sprayer but looking at 'em today they began to appear like giant thermal wicks for interior heat!

3. The roofline slopes through each room from 48 to 60 inches. This means there's a cavity formed by plaster and lath on one side of the rafter and the roof sheathing above. Can you accurately spray to the top plate down this length of cavity? How many passes and time between passes to properly fill this cavity without causing overheating and breakdown of the foam as it cures ?

4. I'm cleaning out the bays of old cellulose. How clean must the rafter sides be for proper adhesion of 1/2lb?

This is a bit long but there's only one shot to get this right and I've probably missed other points already! I'm going with a sprayer with 30 years of experience but it's the guy in the field who makes the job! Thanks for any and all answers.

Scott
Scott Plantier
Posted: Aug 17, 2007 08:16 AM
This might be of service to others beside myself:

The spray company said they wrap the the last foot of chimneys with a fire code thermofiber blanket. Code on the product allows for zero clearance. The sprayer can go right over it. Any thoughts on heat loss for remaining 12' of chimney? Anyone here see chimneys enclosed in 1x3 and foam boards, is it worth my effort?

Blind attic bays-where roof slopes pass through living space so have plaster on one side, roofing above-can be opened by the sprayer with ceiling replacement by me.
I think I'll use an angle grinder/cutoff tool with a very thin diamond wheel and vacum attachment and do the openings myself. This way the openings will be prepared for drywall patch by allowing the lath to extend a 1/2 into the opening. The plaster is scored/removed then lath is cut at a smaller diameter. The rotary tool keeps the plaster lath attachment intact which reciprocating tools often destroy and reduces callbacks from future cracks etc. For those of you offering turnkey spraying, use durabond for the first layer of mud and I can all but guarantee the patch will never fail.

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