No announcement yet.

Roof insolation

  • Filter
  • Time
  • Show
Clear All
new posts

  • Roof insolation

    Hi there,

    This past year we upgraded our attic insulation. The company that did the job for us made us aware fo a slight problem we had with a mustie smell and a minor amount of mildew starting. Our house has had two additions added to it and the builders left the old roof within the new one.. so there was blockages of air flow. The company cut a series of large holes thru the old roof with in our roof to open that up and added some more roof vents, soffit vent air chutes to help air flow... plus sprayed and anti fungal all over the place up there to look after the mustie smell and prevent it in the future. Made sense to us to have this done as you don't want mold happening anywhere. I had been up in the attic area the year before and never noticed anything odd. All dry and very cold.

    The other day, I was pulling out an old shower stall in a bath room we no longer use. behind the stall (on and outside wall) was very wet insulation and the plywood was soaked top to bottom. I pulled a bi-fold door frame out that was on another wall close by.. also wet on top and leaking from up above. 10 feet away I pulled out an access hole the insulators cut in to gain better access to the area above as there was a old roof within the ceiling as well... the access panel also had water in that area above the plastic vapour barrier. This of course freaked me out and made me pop the hatch on the main attic access to have look.. gleaming little water droplets hanging everywhere and basically everything had condensation on it including the underside of the new vents they installed.

    Important facts FYI
    -Roof is asphalt on osb or solid strapping on truss 5 feet of attic space at peak.
    -New windows added this year and Heat pump was also added the year before.. nice and toastie now.
    Home was inspected when we purchased a few years ago and nothing mentioned then. Made us aware of what was up there, said the workmanship was fine and nothing to be afraid of and no mention of moisture problems. what was mentioned at the time in the report was. "Attic ventilation appears in good condition and is performing as intended. If you plan to increase the amount of insulation be prepared to increase the ventilation as well"

    Now by reading all that, I feel that the ventilation is not performing as it should and after paying a proper company to do what they are in business to do.. we now have a huge moisture problem that has crept into our walls and ??? do you think the new insulation is to blame for the climate shift in our attic ?

    thanks for any help you can offer and I am all ears, RonD
    Last edited by RonD; 01-02-2010, 12:03 PM.

  • #2
    Re: Roof insolation

    For roof venting to work properly, you need fresh air coming in through vented soffits and exiting through roof vents or ridge vent.

    Sometimes when new insulation is added, soffits get plugged up, decreasing air flow.

    You mentioned it was a shower tear out you did - could the moisture be from a shower fan that was never properly vented, or the vent was closed over by mistake during the last renovation?

    Simple explanation may be a leak in the roof, especially around a vent that isn't sitting properly or properly flashed.

    Hard to guess without getting an actual look at things - in my experience though, bad flashing is a common culprit in a lot of cases. You mentioned additions on the house - a lot of times a lower roof line butting up against a wall poses a flashing problem with the siding causing leaking.
    I'm on "The List" and I love it!!


    • #3
      Re: Roof insolation

      thanks for the response. the shower has never been used by us in the 3.5 years we have had to house.. so I doubt that would be it.

      there is a ridge vent in place as well all along the entire lenght of the house. the moisture is thru out the entire attic area. and the roof is in good shape.. 10 years old at the most.

      The roofs with in my roof stucture are completely encased in there. The existing roof was built over them with large gaps between them see picture attached to see what I mean. the insulation company cut huge 4' x 16' holes thru the old inner roof to improve air flow

      Click image for larger version

Name:	P7270035.JPG
Views:	1
Size:	146.3 KB
ID:	620330


      • #4
        Re: Roof insolation

        The only thing I can think of now is that those big holes cut in the original roof ain't doing the job for you. Is there a proper air exchanger? If there isn't, and it's an older, tight home,(e.g. condensation on the inside side of the windows when it's cold out) there's too much moisture and not enough areas for it to get out of.

        You cook in the kitchen, take showers, etc., and there's not enough area. When they left the old roof on they should have used a breathable underlayment on it to assist in the air flow.

        But then again, the proper way would have been to remove the old roof and do things right. What's there might pass code, but that's no guarantee of quality. OSB is code approved, and it's crap in my opinion.

        Regardless, I hope you solve your problem soon, otherwise you're going to be pulling down some seriously blackened OSB and insulation.

        The plumbing guys talk about hack work - well, the guys who did the work on your place were probably from Hacktown.
        I'm on "The List" and I love it!!


        • #5
          Re: Roof insulation

          Sounds like to me you need some type of power ventilation in the old attic and if there are any exhaust fans that empty in the attic extend them on out preferable to the outside,
          is the furnace and hot water heater flues extend on out to the out side,
          and plumbing vents ran out side of the new roof?
          Last edited by BHD; 01-03-2010, 10:32 AM.
          Push sticks/blocks Save Fingers
          "The true measure of a man is how he treats someone who can do him absolutely no good."
          attributed to Samuel Johnson
          PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and the current state of the economy............the light at the end of the tunnel, has been turned off.


          • #6
            Re: Roof insolation

            In the one photo you provide, are those the 'water droplets' you are referring to? They almost look like sap which heat can sometimes cause to rise to the surface of the board. But if you were in thee and touched it and know it is water then that's not the case, can't tell from the photo though.
            "It's a table saw, do you know where your fingers are?" Bob D. 2006



            1/20/2017 - The Beginning of a new Error


            • #7
              Re: Roof insolation

              thanks again for the responses everyone.

              BHD. The hot water tank has no vent and every thing the makes its way thru the attic area is vented outside already. This company also insulated a bunch of those as well to cut down heat exchange in that area I am assuming.

              Bob D .. yes there is sap in certain areas but that picture is prior to this moisture problem. looks very similar though.. just ad the musty smell and more droplets.. such a nice treat this time of year. I am so glad I pulled that shower out now... rather than later on when major mold would have taken hold.

              Tinmack.. Air exchanger .. are you meaning in the attic? in which case no. Only ridge vents, roof vents and soffit vents. If your meaning the house.. the heat pump is running.. No moisture around the windows either now that we have gone to vinyl frames in the past year.. prior to that with aluminum frames we did have a minor amount pooling on the sills when it was very cold out.

              I couldn't agree with you more about the proper way to have done this.. which would have been to remove the old roof and build a new.

              I used to frame houses 15+ years ago and still do allot of my own work. The insulation isn't and will never be on my to do list.. I like it almost as much as sanding drywall or banging forms in this time a year in the muck and cold and I would rather pay a company to do the job right as things have changed allot in the past decade in the thinking and technology in which houses breathe. This one apparently has some respiratory illness that needs to be sorted out and I hope these guys that put the insulation in will help to sort it out as we trusted what they said.. another case of you know your business.. we hope ??
              Last edited by RonD; 01-03-2010, 06:43 PM.


              • #8
                Re: Roof insolation

                Well the company came by today and were great. they will be adding in a bunch more soffit chutes and we will hopefully see the climate improve up there very soon.


                • #9
                  Re: Roof insolation

                  I have read of situations where adding attic insulation resulted in this problem. I think the explanation had something to do with the fact that the insulation results in a colder attic but no reduction in the amount of moisture migrating out of the house and into the attic. The result is condensation under conditions where you wouldnt have had it before. The moisture could be coming from air moving out of the house and into the attic through light fixtures, the attic hatch, gaps around pipes, etc. If I remember correctly, the solution in that case was a combination of fillng any gaps with foam and adding a fan to the attic to push the moisture out. Good luck.


                  • #10
                    Re: Roof insolation

                    Besides checking for air leaks from the shower, make sure the soffit vents are open to allow makeup air for the ridge vents.


                    • #11
                      Re: Roof insolation

                      soffit vents should be checked thoroughly so that evrything works well
                      Alabama drywall installation contractors