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  1. #1
    Join Date
    May 2011
    Location
    Montreal
    Posts
    44

    Default Mold after renovation

    Hi there,

    My client has an old 1950 duplex in Montreal. The exterior siding used to be aggregate and they've never had any problem.

    He recently called a company to install Vinyl siding all around the house and he also changed his old windows for a new PVC with thermos model.

    So the contractor simply took off the exterior aggregate siding, he installed +/- 2 inch polystyren insulation panel, then he put the vinyl siding.

    2 Weeks ago, the temperature dropped and we started to have cold weather, thats when they realized they have mold on the bottom of their exterior wall (from inside).

    When I opened the wall, I noticed a funny structure but most importantly that there was no insulation. Only two sheets of plaster before the structure, then you could see the original solid wood siding.

    I didn't notice any mold or humidity inside the wall, but only on the surface of the plaster.

    Here are my questions:

    1 - Why is there mold only on the surface and not inside the wall (since I thought the cause of the problem is the lack of insulation).

    2 - Why is the mold present only on this particular wall and not the others since all the exterior siding has been changed.

    3 - How could an exterior wall hold and support the upper floor weight without 2 x 6 structure like I normally see.

    Sorry for my bad english, I'm french canadian : P

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  2. #2
    Join Date
    Feb 2009
    Location
    Southern Vancouver Island
    Posts
    4,549

    Default Re: Mold after renovation

    The mould is growing on the inner surface only. That is not unusual in a house that is poorly heated. It is likely due to a cold spot, poor air circulation, and moisture in the interior air condensing on the cold surface of the drywall.

    Your client should look at blowing insulation into those wall cavities. A contractor can remove some vinyl, drill holes and blow cellulose in. But since you are pulling drywall already, it can be done from the inside.

    Rough-cut 2X4's are typical for the age of the house. Those studs do look like they are only about 3". That is questionable, for sure.

    Last edited by John Kogel; 11-14-2012 at 09:07 AM.
    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

  3. #3
    Join Date
    Feb 2008
    Location
    Caledon, Ontario
    Posts
    5,005

    Default Re: Mold after renovation

    Part of the problem in photo two - the exterior replacement siding and insulative panels are poorly installed.


  4. #4
    Join Date
    Mar 2007
    Location
    Lake Barrington, IL
    Posts
    1,363

    Default Re: Mold after renovation

    I suspect that part of the problem has to do with how the house now breaths.

    Eric Barker, ACI
    Lake Barrington, IL

  5. #5
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Mold after renovation

    Quote Originally Posted by Eric Barker View Post
    I suspect that part of the problem has to do with how the house now breaths.
    ... or does not breathe ...

    ... at least not like it did in its original state when the house worked with itself and not against itself.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  6. #6

    Default Re: Mold after renovation

    I agree with all the above.


    Caoimhín P. Connell
    Forensic Industrial Hygienist
    Forensic Applications Consulting Technologies, Inc. - Home

    (The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

    AMDG


  7. #7
    Join Date
    Mar 2012
    Location
    Michigan
    Posts
    43

    Default Re: Mold after renovation

    Definitely the air in the home condensing on the wall. That is the reason there is no mold on the inside.

    Everything has its beauty but not everyone sees it.

  8. #8
    Join Date
    Aug 2011
    Location
    Bennett (Denver metro), Colorado
    Posts
    1,394

    Default Re: Mold after renovation

    Quote Originally Posted by Jerry Peck View Post
    ... or does not breathe ...

    ... at least not like it did in its original state when the house worked with itself and not against itself.
    What recommendations would you make?


  9. #9
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Mold after renovation

    Quote Originally Posted by Jerry Peck View Post
    ... or does not breathe ...

    ... at least not like it did in its original state when the house worked with itself and not against itself.
    Quote Originally Posted by Lon Henderson View Post
    What recommendations would you make?
    To contact someone expert in building science to make recommendations on what needs to be done to correct the condition(s) found.

    Not that I did not say for someone to "evaluate" the building - they *HAVE* to do that in order to make their recommendations on what needs to be done, *I* do not need to tell them to "evaluate" the building.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  10. #10
    Join Date
    Feb 2008
    Location
    Caledon, Ontario
    Posts
    5,005

    Default Re: Mold after renovation

    When I opened the wall, I noticed a funny structure but most importantly that there was no insulation. Only two sheets of plaster before the structure, then you could see the original solid wood siding.
    The interior wall due to lack of insulation is now reaching its dew point thus creating favourable conditions for mould growth.

    Also

    Guide to Insulating Sheathing
    Guide to Insulating Sheathing — Building Science Information

    Incidentally how is this house heated?


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