Go Back   BuildingHomes.ca - Building your community! > General > Basement Finishing and Renovations

Basement Finishing and Renovations Has it been 2 years already? Time to work on finishing the basement into some extra living space.


Reply
 
Thread Tools Display Modes
  #1  
Old 2016-12-18, 01:59 PM
PatFlemming PatFlemming is offline
Member
Regular User
 
Join Date: Dec 2016
Location: Orleans
Posts: 30
Default How to prevent moisture behind batt insulation?

Good day all,

I know that in a ideal world, concrete basement walls should be spray foamed or insulated with ridgid foam to create a thermal break.

Well, I'm getting a home build, and typical of minimum code, the basement walls will have pink fibreglass batt insulation with vapour barrier, coming about halfway down the wall.

Based on everything I hear and read, it seems like moisture saturation will be inevitable. Can anyone recommend any best practices or preventative measures I can use to minimize the risk of future moisture or mould problems? My basement is going to be dry walled upon delivery so I dont want to have to rip it all up a few years later.

Thanks
Reply With Quote
  #2  
Old 2016-12-19, 07:22 PM
good2know's Avatar
good2know good2know is offline
Senior Member
Regular User
 
Join Date: Sep 2010
Location: Ottawa
Posts: 5,775
Default

Only one way to prevent it. Don't do it in the first place.

The build itself will trap all sorts of moisture in the wall. The concrete will be wet from condensation. A winter build is the worst.

If they seal the rim joist area all up the moisture has no where to go.

The question becomes how long will it last before it smells so bad I must do something. I have a town built in 93 with insulation like you describe. It's a just a tiny bit musty smell. All carpet is gone which helps.
Reply With Quote
  #3  
Old 2016-12-20, 01:24 PM
PatFlemming PatFlemming is offline
Member
Regular User
 
Join Date: Dec 2016
Location: Orleans
Posts: 30
Default

Thanks for the reply. Good to know what awaits

How do you figure winter builds are worse than summer? Isn't there less condensation in the air in cold temps, and snow doesn't saturate the lumber as much as rain and humidity does?
Reply With Quote
  #4  
Old 2016-12-22, 12:15 PM
good2know's Avatar
good2know good2know is offline
Senior Member
Regular User
 
Join Date: Sep 2010
Location: Ottawa
Posts: 5,775
Default

A common practice is to run propane heaters in the house. One or more commercial heaters that convert the propane into water and co2/co increasing the interior humidity way above recommended levels.

In the basement a lot of this moisture gets absorbed into the concrete. The builder will then cover up the damp concrete with wood, absorbent material and a lovely plastic sheet to seal it all in. All the wood down there has also been absorbing moisture as well as the joists and subfloor. All that moisture can cause problems with the hardwood too.

Air infiltration around the sill plate can allow warm moist air infiltration in summer (bad) which will condense in side the wall and freezing cold air in the winter which freezes as frost or ice inside the walls and joist ends.

Building Sciences has an excellent collection of articles explaining the problems with these minimum code methods.
Reply With Quote
  #5  
Old 2016-12-26, 04:36 PM
PatFlemming PatFlemming is offline
Member
Regular User
 
Join Date: Dec 2016
Location: Orleans
Posts: 30
Default

Thanks for the information good2know!

I believe my builder uses natural gas rather than propane for the drying process. Does natural gas also convert into water?
Reply With Quote
  #6  
Old 2016-12-27, 10:57 AM
good2know's Avatar
good2know good2know is offline
Senior Member
Regular User
 
Join Date: Sep 2010
Location: Ottawa
Posts: 5,775
Default

Yes its pretty much the same.
Reply With Quote
  #7  
Old 2017-01-04, 06:46 AM
JMurphy83 JMurphy83 is offline
Junior Member
 
Join Date: Jan 2017
Location: St. John's
Posts: 2
Default

I am currently researching this same thing which is what brought me here.

I have read in both a book published by Mike Holmes, and on the National Resources Canada website (http://www.nrcan.gc.ca/energy/effici...ion/15639#a6-2)
that if you put 2 inches of foam insulation against the concrete, followed by your stud wall filled with batt insulation, you will not need vapour barrier. Refer to section 6.2.4 on that website.

I haven't completed my basement yet, but I am leaning towards not putting up a vapour barrier and following this method. The only question I have now, is that I already have 1 inch of foam against the concrete and the stud wall is complete. Will I run into problems where I don't have 2 inches of foam?
Reply With Quote
  #8  
Old 2017-01-04, 07:00 AM
good2know's Avatar
good2know good2know is offline
Senior Member
Regular User
 
Join Date: Sep 2010
Location: Ottawa
Posts: 5,775
Default

The closed cell foam must be 2 inch to qualify as the vapour barrier. Always best to consult with building inspectors dept as to what they want to see.
Reply With Quote
Reply

Bookmarks

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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
How to prevent neighbours snow from spilling over? BancroftBoy Ottawa 35 2015-02-17 09:26 AM
Moisture leaking down wall from behind insulation. Snagglepuss Home Owner Tips, Upgrades and Maintenance 1 2013-07-16 08:34 PM
how to repell/prevent Vole (damage) ? James08 Burlington 14 2009-11-13 12:29 PM
Moisture in Basement Behind Insulation amd1 Home Owner Tips, Upgrades and Maintenance 5 2009-06-30 01:03 PM
R-13 Batt Insulation maryandnick Stouffville - Mattamy On Main and Wheler’S Mill 12 2006-10-22 04:39 AM



All times are GMT -4. The time now is 07:57 PM.



Copyright © PHAND Corporation
This document may not be used elsewhere without the expressed written consent of PHAND Corporation.
*** There is no association between this website and any builder. ***

Powered by vBulletin® Version 3.8.10
Copyright ©2000 - 2019, vBulletin Solutions, Inc.