Insulation To Fit Between 4-inch Rafters - Insulation - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Insulation


Thread Tools Display Modes
Old 05-19-2012, 07:58 PM   #1
Join Date: May 2012
Posts: 2
Rewards Points: 12

Insulation to fit between 4-inch rafters

After we knocked out a chimney and our kitchen ceiling for a home remodel, we discovered a relatively roomy attic space above the kitchen, which we are now finishing so we can make use of it. However, right now there is no insulation between this attic space and the roof. I want to change that before the hottest part of summer arrives.

The rafters are 4-inches deep, meaning we can only have insulation about 4 inches thick. A building inspector who was checking off part of our project told my wife that there is some kind of foam insulation that would fit in that space but still have a pretty high R value... But so far we haven't had any luck finding anything that will do the trick.

I'm currently considering a combination between some kind of foam insulation and radiant foil to help shield the new room from the worst of the sun's heat. Could this work?

I'd like to hear any other suggestions on how to insulate this area. Thanks!


bgent is offline   Reply With Quote
Old 05-19-2012, 11:18 PM   #2
Exterior Construction
Windows on Wash's Avatar
Join Date: Aug 2011
Location: Washington DC Metro Area (VA, MD, DC)
Posts: 10,105
Rewards Points: 7,430

Insulation to fit between 4-inch rafters

Radiant foil needs an air space to work.

Rigid polyiso is going to have the best R-value but still won't be adequate at 4".

You will need to look critically at the venting as well and moisture control.


Windows on Wash is online now   Reply With Quote
The Following User Says Thank You to Windows on Wash For This Useful Post:
Ravenworks (05-20-2012)
Old 05-20-2012, 06:46 AM   #3
Join Date: Nov 2011
Location: Hartfield VA
Posts: 30,763
Rewards Points: 6,642

Insulation to fit between 4-inch rafters

Is this space even able to be converted.
By far most attic were never designed for use as a living space or even storage space.
The biggest issure is the width, spacing and span of the joist.

There needs to be a ridge vent, soffit vents, baffles for air flow from the soffits to the ridge vents before any insulation ever goes in. With just 2 X 4's that would only leave room for 1" of insulation.
joecaption is online now   Reply With Quote
The Following User Says Thank You to joecaption For This Useful Post:
Ravenworks (05-20-2012)

attic conversion , insulation , radiant foil , rafters

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Cape Cod Style House Attic/Crawl Space Insulation Help Danielg Insulation 24 05-21-2012 09:20 AM
1 1/2 inch foam insulation jburchill Building & Construction 8 06-15-2011 10:59 PM
Rafter Vents and Insulation nofx1981 Roofing/Siding 15 03-10-2010 09:14 PM
How hard to install insulation yourself? techprincesse Building & Construction 26 10-17-2009 10:57 AM
Old home insulation woes nowwhatnapster Building & Construction 15 11-03-2008 12:59 AM

Top of Page | View New Posts