Need advice re:no sarking in roof, problems with ceiling and roof ventilation

patthecat on 18/11/2018 - 11:37

Hello

https://files.ozbargain.com.au/upload/136176/63990/img_0294.…
https://files.ozbargain.com.au/upload/136176/63989/img_0292.…
https://files.ozbargain.com.au/upload/136176/63987/img_0289.…
https://files.ozbargain.com.au/upload/136176/63991/img_0293_…

We have brought a 30 year old house that was owner builder built and never quite completed.

It has a colourbond roof with no sarking or whirly birds. There is also no insulation of any kind.

It has three ventalation holes either side of the roof (see pics). The eaves have never properly been completed. They we open on each side until recently when we completed the front one, the back ones are still open (see pics)

So over the years water has come in through the roof vent holes and caused the ceiling on both sides to some down. One side had already happened before we brought and the other side came down recently.

When we painted the ceiling in another part of the house the wet paint made the ceiling paint bubble. We think its due to damp.

We had a gyprocker quote us who said that the side vents in the roof were a real problem and that he was concerned we had no sarking.

A roof plumber came out and said cost to retro fit sarking would be about 10K and we probably wouldn't see enough benefit to make it worth while. He pointed out that older weatherboard houses has no sarking either.

So we are about to do some renos including an expensive skylight and solar panels and we need to make sure nothing needs to be done with regards to sarking after this.

So my questions are: Are there any alternatives to putting sarking in? Would putting insulation batts in help soak up any moisture? Should we close up the side holes to prevent rain from entering and install whirly birds? Will this be enough ventilation ?

Thanks for taking the time and reading so far. We cant decide what to do for the best. We don't want to get anyone out to ask for advice as dont want to waste their time. Thought this might be a good place to ask for other opinions. Any help appreciated.

Home & Garden

Comments

  • myusername on 18/11/2018 - 11:56
    +1

    bulldozer

    insulation batts will soak up the moisture, but will eventually turn into a mould factory

    we just had out roof restored (tiles) we have no sarking in our house either.

    • patthecat on 18/11/2018 - 12:06
      +1

      Yes, bulldozer has crossed my mind several times.

      My husband thinks the ceiling batts are the solution, I agree they will soak up the moisture and then possibly become a heavier weight on ceiling.

      • myusername on 18/11/2018 - 12:17
        +2

        ceiling batts are a great short term solution only if you remove after they've soaked the moisture up. otherwise you just increased the amount of mould in your roof space

  • Nugs on 18/11/2018 - 12:34

    "never quite completed."

    understatement.
    .

  • chumlee on 18/11/2018 - 12:41
    +1

    Why dont you just put some kind of cover over the vents so rain doesn't get in?

    How many other quotes did you get for the roofing job?

  • hawkeye on 18/11/2018 - 12:47

    I'd go whirlybirds and a heap of vents when you put the soffits back in to try and reduce condensation bats wouldn't hurt depends how much cash you want to throw at it.
    http://www.bluescopesteel.com.au/index.cfm?objectID=DFB88DCF…
    If you want to sark it use this and problem would be gone
    https://www.pricewiseinsulation.com.au/product/light-duty-fl…

  • patthecat on 18/11/2018 - 13:11

    Nugs - "never quite completed" - you don't know that half of it.

    chumlee - 'Why don't you just put some kind of cover over the vents so rain doesn't get in?' - we could (will have to) cover them but will need alternative ventilation ie whirly birds. Don't think it will solve the main issue of no sarking / condensation either. Will get another quote if sarking is the to go, just looking for any alternatives.

    Hawkeye - Soffit vents look like a good idea (had to google soffit) The insulation that you mention - does this directly under the roof (as sarking would) or on the ceiling as insulation would? Thanks

    Thanks again for your time

  • hawkeye on 18/11/2018 - 13:36

    wool side up sandwiched between the batton and roof sheet.
    The 3 earthenware pipes on the gable weren't cut out neatly in the brick to pass through for decoration they're there for the same reason to ventilate the ceiling.
    If it was for a facade they would have just glued it to the brick without going to all that trouble

  • ihbh on 18/11/2018 - 16:38

    probably wouldn't see enough benefit (of retro fitting sarking) to make it worth while

    What benefit are you looking for?

  • subywagon on 18/11/2018 - 17:50

    You could always install the sarking yourself if the colourbond is screwed down. Just unscrew it and complete it section by section over a few weekends. I did this myself with a shed recently. Also I'd put some kind of cover over the ventilation as suggested to stop rain coming through. Insulation in the roof would be easy, just install bats yourself.

  • outlander on 18/11/2018 - 18:55
    +5

    Here is the situation as I see it:

    Water is not coming in through the ventilation pipes. Rain falls vertically, not horizontally. For it to move horizontally, wind has to blow it, and it would take some incredibly strong wind to blow water droplets 30cm horizontally. Your problem isn't with the vent holes, its with the eaves.

    When the last owner was building it, he probably thought as long he put the roof up, it would be okay. After all, water only falls downward, right? The soffits are optional, only there for aesthetic reasons, right? Well, no. Rain might only fall down, but moisture can move in any direction. Moisture is in the air always, but it varies throughout the day. Warmer air holds more moisture than cooler air. So what happens when you take warm humid air, and cool it down? The excess moisture comes out as a free liquid, also known as condensation.

    You know condensation? That thing where you come out to your car in the morning, and the grass is all wet despite it not having rained? Well, your house is acting as a condensation trap. Throughout the day, the sun heats up the ground and air around it, causing it to absorb moisture. This moisture-rich air rises up up up, and with no soffits to stop it, it ends up in your roofspace, where the triangle shape of the roof traps it. Some of this air escapes through the vent holes, but not enough to make a difference. The moisture rich air builds up enough to contact the topside of the ceiling. This part is naturally colder than the rest of the roof, especially so if you're running air conditioning in the room below, so the moisture-rich air cools down a bit, and creates condensation. This is readily absorbed by the plasterboard ceiling (The main component of plaster is calcium carbonate, which is very greedy when it comes to water and will grab it out of the air and not let go)

    Main thing to emphasize here is that this is a slow process. Even very very humid air doesn't hold much water, so it may only be depositing as little as a quarter of a cup of water a day over the entire roof space. But it's happening ever.single.day.The plaster ceiling never has a change to dry off. The water just keeps building up, until eventually the plasterboard is too heavy and falls down.
    The only chance it has to shed water is on the other side, the side you can see from inside. Which is why when you painted it, it started to bubble and pop, as the water containing in the plaster board built up.

    You can verify this by putting a hygrometer in the roofspace, and checking the humidity throughout the day. Often cheap digital clocks have them.

    On to solutions. You can put on soffits, and that would be a good start, but the fact is that your roof space is already ladden with moisture. To get that moisture out will require high ventilation for a couple of weeks at least. Whirlybirds aren't going to cut it here I'm afraid, you need something powered. You also want to check very thoroughly for wood rot and mold. If thats present your in trouble.

    You can put battens and sarking down now, but that does nothing for the moisture already trapped inside the board.

  • Lennox on 19/11/2018 - 01:57
    +1

    So further to the aforementioned, i would also look at your eaves and perhaps getting these finished asap as well and look at installing a stormwater drainpipe to carry the extra flow of water and stop the pressure on the eaves as well.

    The timber looks clean to me and i cant see any rot in the pictures but that doesnt mean its not there. Hardwood was usually used in these older homes and is quite resistant to the changes in tempertaure better than modern day homes that are built with radiata pine which bend and fracture more easily.

    In terms of the moisture content you need to get this under control first before doing anything as well as looking at what boards you can save and what you need repaired. I would suggest you look at the balanced and exhaust type ventilation systems. It seems to be cost effective.Talk to a professional and see what they recommend.

    Once you regulate this it will be alot easier.

  • outlander on 07/12/2018 - 13:54

    Care to follow up on this?

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