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  • Condensation on a ceiling

    A new Zealand house construction is usually dry wall or as we call it Gib board on timber framing with Batts insulation between.
    I have re dry walled my whole old house including ceilings over the last 4 years making sure the insulation is correct, the only ceiling I have not done is the bedroom I use its a ceiling about 3m wider and 5m long so not small it is a product we call fiberouse plaster as in "plaster of paris" held together with fiberglass strands, this bedroom was an addition on the house in 1984 when insulation was new on the market and the ceiling is in good condition (unlike what the rest of the house was) the house was re roofed 4 years ago.
    When I first moved into the bedroom I noticed 2 areas had condensation on them it was actually forming drips of water I had to wipe dry it has not to my surprise happened since or maybe I don't look, I used to look, in winter to bedroom is the coldest room in the house at night but then its far from the heat source, there is very little space above the ceiling and I cannot get into it, no crawl space.
    I am thinking I will rip down a good ceiling as I think the areas that condensated must have no insulation above I think in 1984 the thinking was that any insulation was good enough so it is probably thin batts maybe it was split in half to save cost.
    When the house was built 8' was the stud / room standard now we use 2.4m which is 40mm less, the passage that leads to the ensuite is 40mm lower so I have a 40mm step that I could loose if I drop the ceiling as part of the relining process.
    My question to those who read this is.
    Why that condensation in just 2 areas?
    Why is that room so cold under floor and walls are insulated and double glazed windows?
    It would cost me about $1200 and a little over a week to do it, my time is free, I would rather be playing with wood than dry wall but then the insulation condition will always be on my mind, what would you do???????
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  • #2

    Re: Condensation on a ceiling

    That's definitely warm air meeting cold ceiling. Is there no way you can access the space above it?? You could drill a hole in the center of the condensation and inject spray foam and see if that would cure the problem. Are these just small areas or larger ones?

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    • #3

      Re: Condensation on a ceiling

      Cold=furthest from heat source, poor insulation, thermostat location (it gets warm before bedroom) - if you can't reach the bad areas maybe they couldn't. Ceilings with inadequate insulation are typically the biggest heat loss areas other than glass panes.
      Condensation in 2 areas could be due to warm air circulation patterns where it gets trapped at cold spots and condenses.
      Is blown-in type insulation an option to reach the unreachable areas - remember you still need cold air circulation above the insulation?
      You won't be happy until you fix it.
      billh

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      • #4

        Re: Condensation on a ceiling

        What if you were to put ridgid insulation (styrofoam) on top and put drywall on top of that. Thats what I am doing with my house I have 18 inches of insulation in attic with 1x6 shiplap on ceiling then 12''x12'' tiles no vapour barrier. I put 1 inch strofoam up then 5/8 drywall on top. And my walls are 2x4 with insulation and vapour barrier and 1/2 drywall. I put 1 inch styrofam and 5/8 on top mark my studs . don't take anything off, so no dump trips.

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        • #5

          Re: Condensation on a ceiling

          Hi Bob.

          Here's the layers you would want to have in order to eliminate condensation and the resulting water.

          Going upwards from the ceiling to the roof; Drywall, Vapour Barrier, Insulation, air space, underside of roof sheathing, Roof sheathing including air vents, Roofing Membrane, Shingles. If your roof is flat things can get a bit different.

          In your example the air venting might be difficult and making suggestions without knowing how things are built/done in New Zealand is perhaps useless information.

          It sounds to me like your best bet would be to remove the ceiling plaster you have which is probably applied to some type of lath material, metal or wood. Remove it all including the lath. Insulate between joisting, apply a poly Vapour Barrier and the drywall board. Tape and paint to finish. Not being familiar with climate and temps is tough as well but insulation can keep you cool too.
          "Do it Right!"

          Comment


          • #6

            Re: Condensation on a ceiling

            Check out the attic venting first.

            Then, most likely, Insulate and improve venting. The quick fixes may not be the best so just redo the entire ceiling. You may find condensate damage and or mold In the attic area.
            Egon
            from
            The South Shore, Nova Scotia

            Comment

            • Thread Continues Below...

            • #7

              Re: Condensation on a ceiling

              Seeing that it is summer there now are you getting the condensation now? if so look for AC ductwork touching the plaster.
              Jerome
              Canada's South Coast

              Port Colborne On.
              Every loaf of bread is a tragic tale of grains that could've become beer.......but didn't....

              Comment


              • #8

                Re: Condensation on a ceiling

                Originally posted by Rusty View Post
                Hi Bob.

                Here's the layers you would want to have in order to eliminate condensation and the resulting water.

                Going upwards from the ceiling to the roof; Drywall, Vapour Barrier, Insulation, air space, underside of roof sheathing, Roof sheathing including air vents, Roofing Membrane, Shingles. If your roof is flat things can get a bit different.

                In your example the air venting might be difficult and making suggestions without knowing how things are built/done in New Zealand is perhaps useless information.

                It sounds to me like your best bet would be to remove the ceiling plaster you have which is probably applied to some type of lath material, metal or wood. Remove it all including the lath. Insulate between joisting, apply a poly Vapour Barrier and the drywall board. Tape and paint to finish. Not being familiar with climate and temps is tough as well but insulation can keep you cool too.
                As i said Rusty I have replaced every ceiling and wall in the whole house except this one that is in good condition dry wall wise, the roof was replaced first to eliminate any water ingress, some parts of the house the roof was possibly 70 years old and had been leaking, I had made sure all the insulation was correct except for this ceiling as I cannot get above it its a shallow pitch we don't get snow only maybe 6 frosts a year, 99 percent of roofs are corrugated tin these are good in an earthquake as there is still something to shelter under and we are prone to earthquakes there is nothing better in my book, we only put a building paper tar paper to eliminate condensation on the back of the tin dripping onto the ceiling where the corrugated tin meets the outer edge by the gutters there are plenty of gaps that create a ventilation for the roof space, under the tar paper goes a chicken wire to prevent sag in the building paper, my soffits are lower than the ceiling so there is little space for insulation around the outer walls it is also very difficult to get to that area from in the roof space with such a shallow pitch so insulation is best done from below before the ceiling dry wall is put in place, all these houses were built before insulation was thought necessary 1930 and on most around the 1950 even houses built today are much the same but built using trusses not rafter roofs its a well proven method for this climate, we never use a moisture barrier behind the dry wall but we do put in 2 rows of nogs when our stud walls are built, this house has 4" of brick then a 2" gap for the movement of air the bricks are tied to the stud walls with steel ties, on the outer side of the studs is a building paper now we use the same tyvak paper you do the space between the studs is filled with a batts kind of insulation then dry wall taped plastered and painted, a new house near by has used a blown in foam as you do but it is new to NZ.
                This house is not lath and plaster but a plaster of paris sheet product that was made off site brought in and fixed in place using drywall adhesive and screws, it actually withstands a leaking roof better than drywall.
                I am now thinking the insulation is thin as in 1984 it was a new product and possibly thought of as un necessary in a bed room it could also have been kicked aside when the new roof was put on hence the patches that get condensation forming.
                I will go through with a steel ceiling batten system to drop the ceiling that 40mm and make sure it is flat, those steel battens are very true and easy to get correct and no more costly than wood, this is how I have done the whole house.
                Thanks for your help

                Comment


                • #9

                  Re: Condensation on a ceiling

                  Originally posted by Wally in Calgary View Post
                  That's definitely warm air meeting cold ceiling. Is there no way you can access the space above it?? You could drill a hole in the center of the condensation and inject spray foam and see if that would cure the problem. Are these just small areas or larger ones?
                  Thanks Wally your first sentence says it all, no access from above and spraying in foam is hit and miss then it could be touching the roof and that is a no no here, see above.
                  Wally in Calgary likes this.

                  Comment


                  • #10

                    Re: Condensation on a ceiling

                    Originally posted by Jerome View Post
                    Seeing that it is summer there now are you getting the condensation now? if so look for AC ductwork touching the plaster.
                    No AC duckting any where near, my roof space is so hot during the day its hard to sleep some nights its 25degrees at night, I sleep with all the doors open hoping to cool down.
                    I have a white roof hoping the keep the roof space cooler most houses go for dark colours and I believe that leads to a lot of movement of both wood and steel roofing, I have a dark guttering and I can hear it expand and contract as the clouds move overhead.

                    Comment


                    • #11

                      Re: Condensation on a ceiling

                      Bob In your situation and climate,,,, insulation would help for sure. Your problem is where and how to put it??? Dave from South Porcupine mentions a method above that may work for you. If you put your Steel battens up and put styrofoam between them and then added drywall you would get at least some insulation added to the ceiling. The only thing I would do in addition is paint the ceiling you have as your first step. Good paint is a good vapour barrier and in this case I can't see how it would cause any issues.

                      BTW I have no clue what nogs are?
                      "Do it Right!"

                      Comment

                      • Thread Continues Below...

                      • #12

                        Re: Condensation on a ceiling

                        Originally posted by Rusty View Post
                        Bob In your situation and climate,,,, insulation would help for sure. Your problem is where and how to put it??? Dave from South Porcupine mentions a method above that may work for you. If you put your Steel battens up and put styrofoam between them and then added drywall you would get at least some insulation added to the ceiling. The only thing I would do in addition is paint the ceiling you have as your first step. Good paint is a good vapour barrier and in this case I can't see how it would cause any issues.

                        BTW I have no clue what nogs are?
                        F Y I nogs (dwangs) are the short horizontal pieces of wood that are nailed between the studs, in NZ we would put in 2 rows that is in a 2.4m stud height so at 800mm centers, our max stud centers are 600mm to my thinking for 10mm gib board to span 600 X 800mm is too much but that is how most houses are built here, our studs are mostly 4 X 2.
                        A house I built in 1991 in Auckland I insulated entirely with polystyrene, under floor, walls and ceiling it is a good product as it stays where its put and can be removed for maintenance then replaced the down side was getting rid of the rubbish.
                        This house has a mixture of the new polyester (ground up milk bottles) fiberglass and earth wool.
                        I am leaning towards removing the bedroom ceiling installing steel battens earth wool between and re use fiberglass maybe double thickness and re gib, I'm home alone for 10 weeks so can make all the mess I want spend what I want and drink beer when I want.

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