How Should I Upgrade And Insulate My Flat Gravel And Tar Roof - Roofing/Siding - DIY Home Improvement | DIYChatroom


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Roofing/Siding

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 03-01-2013, 03:05 PM   #1
Newbie
 
Join Date: Mar 2013
Posts: 3
Rewards Points: 10
Default

How should I upgrade and insulate my flat gravel and tar roof


I have a house built in 1951 with open beam (2x8 and 2x14) ceilings. They are sheathed in 1x4 and 1x10 tongue and groove sheathing respectively. The sheathing is covered in felt, hot mop, and pea gravel. The roof is leaking and needs to be replaced. I want to tear off the old roof, build it up with blue wood 2x2 or 2x3 stringers on top of the sheathing in line with the joists, insulate the space between the new stringers, top it with blue plywood, and cover the plywood with a commercial membrane. Should I have some kind of vapor barrier and what kind of insulation would be best to use in this situation. I live in Southern California and want to keep the heat out of the house in summer and in the house when it gets cold at night.

Advertisement

Boy Genius is offline   Reply With Quote
Old 03-01-2013, 03:42 PM   #2
Doing This Way Too Long
 
Join Date: Jun 2008
Location: North Idaho
Posts: 1,160
Rewards Points: 524
Default

How should I upgrade and insulate my flat gravel and tar roof


Only have time for a quick reply right now so not real detailed.

No need for all the framing and sheeting. Just look into installing polyiso rigid insulation under the new roofing (regardless of type) after the old roof is demo'd.

It is the ideal time to add insulation in a flat roof and the ROI is there in time so don't necessarily look at the added expense as lost money. Polyiso r-value is around 6 per inch so go from there. Usually commercial specs are 4-6" and done in staggered layers to improve the thermal value. Vapor barrier, if required, is simple 6 mil visquene under insulation.

The only place you need added framing is larger penetrations and around the perimeter to match the profile to the increased height of the insulation.

Lastly a layer of rec board or densdek for fire rating and the new roofing is installed over that.

If you already plan on a new roof, now is the best time to get all of this done correctly.

Sorry, gotta go

Advertisement

OldNBroken is online now   Reply With Quote
Old 03-01-2013, 05:04 PM   #3
Roofmaster
 
Join Date: Oct 2012
Location: Maryland
Posts: 3,669
Rewards Points: 2,096
Default

How should I upgrade and insulate my flat gravel and tar roof


If you have gotten 61 years out of your existing Built up Roof, I would say that is one hell of an advertisement for another BUR. The rule of thumb over wood is to mechanically fasten a sheet of red rosin paper, and a fiberglass base sheet to the deck then mop from there up.

Are you sure that your deck is only 3/4 of an inch thick? what is the spacing on your exposed joists?
__________________
" A lot of men build things, and a lot of things fall down "

jagans is offline   Reply With Quote
Old 03-01-2013, 09:30 PM   #4
Newbie
 
Join Date: Mar 2013
Posts: 3
Rewards Points: 10
Default

How should I upgrade and insulate my flat gravel and tar roof


I need to insulate the roof... I'll look into the Polyiso. I'd like to use more
modern materials that will resist moisture since I'm in a marine environment. Thanks for the quick reply.
Boy Genius is offline   Reply With Quote
Old 03-01-2013, 09:41 PM   #5
Newbie
 
Join Date: Mar 2013
Posts: 3
Rewards Points: 10
Default

How should I upgrade and insulate my flat gravel and tar roof


The 2x8 joists are on 24" spacing with 1x4" t+g sheathing. The 2x14 joists are on 48" spacing with 1 1/2x 10" t+g sheathing. Custom home, custom headaches...
Boy Genius is offline   Reply With Quote
Reply


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





Top of Page | View New Posts