Cold Flat Roof - No Space For Ventilation...? - Insulation - DIY Chatroom Home Improvement Forum
Advertisement


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

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

Reply
 
Thread Tools Search this Thread
Display Modes
Old 05-26-2015, 05:40 PM   #1
Newbie
 
Join Date: May 2015
Posts: 1
Rewards Points: 2
Default

Cold flat roof - no space for ventilation...?


Hey guys,

I'm doing renovations to my old 1905 house in the Netherlands, and I'm running into issues with our flat roof.

Basically, our roof has a terrace above. The roof already has flat windows installed, so we cannot have a warm roof as the extra height would be too much.

Previously, there was plasterboard inside on the ceiling, but *no* insulation. So I guess condensation was not an issue. Plus it was not a 'livable' roof, so it was done on the cheap - I guess.

So I went with the idea of having a cold roof. My problem is that I simply cannot have ventilation. The joists run adjacent with the house. At the front side, we have the house (multiple stories) - so we can't put a vent. We also can't do a wall vent because there are big double doors going out to the terrace.

At the other end, at the end of the house, is the neighbours house. This time it is also only 1 story, so we have the option of having some kind of vent on top of the roof - but is that an option? I've only seen vents on the wall, between the joists.

Is it possible to do this another way? Perhaps having some kind of device that circulates air? Or perhaps vents on the top of the flat roof? And if so, can I somehow have a single vent instead of multiple vents between the joists (that would be a total of 14...

Any help would be appreciated. I'm stuck.

I've attached some pictures. They are, in order:

- facing the front of the roof, where the rest of our house is
- the back wall. Neighbours house behind this wall.
- same as above
- view of the roof from above, looking towards the neighbours.
Attached Thumbnails
Cold flat roof - no space for ventilation...?-img_2190-1-.jpg   Cold flat roof - no space for ventilation...?-img_2189-1-.jpg   Cold flat roof - no space for ventilation...?-img_2188-1-.jpg   Cold flat roof - no space for ventilation...?-img_2183.jpg  
rdougan is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-26-2015, 06:52 PM   #2
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: Washington DC Metro Area (VA, MD, DC)
Posts: 26,064
Rewards Points: 928
Blog Entries: 41
Default


Is the roof being re-done?

You could strap the roof and create a new vent space above but if not, the easiest thing is probably SPF in this case.
Windows on Wash is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-26-2015, 08:43 PM   #3
Registered User
 
Join Date: Mar 2009
Posts: 11,730
Rewards Points: 526
Default


Welcome to the forum!

Another option is R-15 rigid foam board (XPS or EPS w. vapor barrier) insulation tight to roof decking and canned foam the joints/perimeter. That would give you 43% Relative Humidity in the house before condensation (board sheathing at 44*F), same as Zone 4a (see map) here; http://www.buildingscience.com/docum...n-roof-venting

Gary
__________________
If any ads are present below my answer or words underlined/colored, I do not condone/support/use the product or services listed/linked to, they are there without my consent.
17,000 dryer fires a year, when did you last clean the inside of the dryer near motor or the exhaust ducting?
Gary in WA is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
Best kind of roof for flat garage roof..? NewHomeDIYGuy Roofing/Siding 13 08-14-2013 10:46 AM
Cold flat roof construction Ding1e Roofing/Siding 4 08-19-2011 03:09 PM
will a flat roof always leak............. cappuccino Roofing/Siding 6 04-19-2011 04:16 PM
Blown Insulation - Flat roof AndrewF Roofing/Siding 1 12-31-2009 06:41 PM
Flat roof - Rolled? - leaks Advice? JJ2001 Roofing/Siding 4 11-19-2006 06:17 AM




Top of Page | View New Posts