I have a flat roof home with 3 feet of clearance from attic floor to ceiling. It is 1920 square feet, existing home. The space is unvented, and has one access hatch. It is in the master bedroom closet with no close access to a window or door. We plan to spray foam the roof deck. I am struggling to figure out how to ventilate the space during the job without positively pressurizing the attic. The home is stucco, so we do not have an easy way to create a hole to the outside. I typically rent a manhole fan. We can't suck air out of the hatch since overspray would ruin the rented fan (I think, maybe not?) When it is gables, I just leave the gable vents open(or mushrooms) until the very end of the job, and have the fan blow up into the attic hatch and out the gable ends. How do you spray foam guys ventilate an unvented attic space while spraying? We have just started on retrofit market, so most of our jobs have been new homes without these problems.

Views: 314

Reply to This

Replies to This Discussion

Hi Craig,

No direct experience in what you asked, but I have seen the venting process used for asbestos abatement.  In your case, an exhaust fan pulling through a large flex duct down through that hatch and extended as far as necessary.  I have a window fan that roars and I have used it to enhance an IR inspection when the blower door was not part of the consultation.  So even if the fan got contaminated, they aren't that expensive.  A round duct through a square hatch should leave plenty of room for fresh air.  Just thinking out load, good luck.

Bud

Bud - I think that is what we decided, except I will seal the exhaust fan in tight in the hatch, run a 20" flex duct to the outside. Keep a window open and allow the recessed cans to let air into the attic. If that isn't enough air we can always open a supply duct since the attic will be depressurized. Came down to finding the right combo of fan and duct. Can get both for around $100 total. I think the fans will hold up even with some overspray.

There are paper hoods that hook to your compressor hose.  Very slick and inexpensive.  Much better than counting on face masks. 

RSS

Welcome to Home Energy Pros

Welcome to Home Energy Pros – the unique digital community by and for those who work in the home energy performance arena.

Home Energy Pros was founded by the developers of Home Energy Saver Pro (supported by the U.S. Department of Energy) and brought to you in partnership with Home Energy magazine.  Home Energy Pros is sponsored by the Better Buildings Residential Network. Please honor our Guidelines

Blogs

First-Ever Comprehensive National Standard Practice Manual is Updated Guidebook for Energy Efficiency Cost-Benefit Analysis

Posted by Home Energy Magazine on May 23, 2017 at 9:30am 0 Comments

The first-ever comprehensive national guide for utility-funded energy efficiency programs is now available to help utilities, regulators and other interested…

Continue

New Video and Course on Solar PV in Real Estate

Posted by Amber Vignieri on May 16, 2017 at 11:31am 0 Comments

Real estate professionals who understand the basics of solar and know how to market the benefits of an installation will have a market edge. For most real estate agents and appraisers, assessing the value of solar is a new…

Continue

What Happen to Energy Upgrade California?

Posted by Will johnson on May 15, 2017 at 11:43am 0 Comments

Energy Upgrade California offers rebates up to $6,500.00 in SDGE territory.  Up to $4,500 in other territories.  Unfortunately they don't/won't promote it.  I can't get straight candid answers from the contractors supporting the program.  Only…

Continue

Latest Activity

Home Energy Magazine posted a blog post
9 minutes ago
Home Energy Magazine posted a video

Gary Nelson, The Energy Conservatory

Gary Nelson- Home Energy Magazine's "Legends of Home Performance" video series. Interviews with pioneer pathfinders of energy and water efficiency.
11 minutes ago
Kelly Vaughn posted a blog post
1 hour ago
Andrew Etue added a discussion to the group Job Board
Thumbnail

Washington State Seeks Weatherization Field Monitor

Washington State Department of Commerce in Olympia, Washington is recruiting for a Weatherization…See More
19 hours ago

© 2017   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service