Repairing Butynol

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ventolin

104 posts

Master Geek

Topic # 113344 14-Jan-2013 15:21

Hey all

I purchased a home around 6months ago, now it used to have a carport which they converted into a garage.
On top of the carport is your standard wood slats and then they have laid what I think is hardyboard and then over the top of that Butynol, the greyish type stuff.

Now I knew that it would need some work when I brought the place so that isn't a problem. In the past it looks like people have dropped things and broken small holes in the Hardyboard which you can feel walking around on the deck there isn't many of these maybe 4 or 5. However my main problem is there are a few leaks that are dripping into the garage these seem to be only in a few of the joins. I want to get these fixed so I can gib the roof and put ply on the walls. Anyone have experience with this stuff or am I better off getting someone in?

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Reply # 744610 14-Jan-2013 15:37

How long ago was this conversion from carport to garage done? Does it have a council consent (and is it listed as a garage on the title or LIM)

You generally don't need a building consent for an open sided carport, but if you close it in you need a council consent, so before you think about spending money on upgrading it, just check that it is actually legal in the first place.....

You could use something like silicon to bodge up the holes, but if you are using the roof as a deck, I would want to get it done right- get some one in......

ventolin

104 posts

Master Geek

Reply # 744613 14-Jan-2013 15:42

Hi Sorry for lack of information, the Garage is currently boarded in and has been for 20+ years, is listed on the title etc. I am wanting to enclose the inside of the garage to make it tidier, at the moment it's just beams and the stuff they used to board in the outside. The top of the garage is a proper deck and would have been when it was a carport, sliding doors from lounge step out onto the deck and it is fully fenced in.

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mattwnz

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Reply # 744617 14-Jan-2013 15:45

Pretty sure butynol has to be laid on proper plywood, 18mm min thickness., which would have prevented that problem with holes in teh substrate. I think you are going to need to reroof it.Genreally the ply could be laid over the top, so may not be a major job. But I doubt you can patch it, as it sounds like the problem is the substrate, not the butynol.

Is the roof angled? I beleive the building code has recently changed to increase the fall of roof decks.

You will very likely need to get someone in. That sort of problem possibly should have been picked up in a building report.

ventolin

104 posts

Master Geek

Reply # 744628 14-Jan-2013 15:51

The leaks are only where the deck meets the concrete footpath, not where these holes are. The building report was done by a family member who is a builder, they did point this out to me but I chose to purchase the house anyway as it's only a garage below which only houses our cars nothing else.

mattwnz

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Reply # 744632 14-Jan-2013 15:57

ventolin: The leaks are only where the deck meets the concrete footpath, not where these holes are. The building report was done by a family member who is a builder, they did point this out to me but I chose to purchase the house anyway as it's only a garage below which only houses our cars nothing else.

It sounds like you have either a drainage problem or a flashing one, which is potentially more difficult to fix. It shouldn't leak at the joints, becuase it should be lapped and sealed. Not unless it is draining into a hole in the joint, but that could suggest an installtion problem and the joints being laid in the wrong direction to the fall.. Impossible to tell though without looking at it. Maybe some photos mayhelp. Also your say it is laid over some hardie board type product which sounds concerning. Are you sure this isn't asbestos sheeting, as floors and roofs back in the 60's and 70's used this material alot, and if so that could be an expensive problem to get someone in to remove. You may have asbestos dust around if it has broken, which is a major problem.

I think you may need a butynol specialist to look at it. You can also look at bitumen, and TPO membranes as replacements.

ventolin

104 posts

Master Geek

Reply # 744639 14-Jan-2013 16:10

I'm almost positive it is hardyboard as I recall looking at the writing from underneath. I believe it is leaking because the joins around this certain area have lifted a little.

However I do want to replace this stuff with something in the future.

The below product looks nice, do you have an idea what that stuff is kinda worth?

http://www.vikingroofspec.co.nz/catalog/product/dec-k-ing-pvc-waterproofing-membrane

mattwnz

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Reply # 744649 14-Jan-2013 16:30

ventolin: I'm almost positive it is hardyboard as I recall looking at the writing from underneath. I believe it is leaking because the joins around this certain area have lifted a little.

However I do want to replace this stuff with something in the future.

The below product looks nice, do you have an idea what that stuff is kinda worth?

http://www.vikingroofspec.co.nz/catalog/product/dec-k-ing-pvc-waterproofing-membrane

I beleive Hardies though uses to make asbestos back in the 60's Depends on the age. It may have the words asbestos free on it.

I beleive you are unlikely to get any warranty with any membrane unless it is installed on the correct substrate, so you would need to check what they require. 18mm plywood is normal. Pretty sure it has to be installed professionaly, so they would liekly need to lay a new substate anyway. Certainly if the existing substrate has holes/dings, and holes can be easily made in it, it almost certainly isn't suitable.

ventolin

104 posts

Master Geek

Reply # 744650 14-Jan-2013 16:33

Oh definately, I will be looking to get this done at the same time. It is just hard to get a ballpark figure on what it is going to cost as this is my first home I have no experience.

mattwnz

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Reply # 744661 14-Jan-2013 16:49

ventolin: Oh definately, I will be looking to get this done at the same time. It is just hard to get a ballpark figure on what it is going to cost as this is my first home I have no experience.

Impossible to know without knowing area and work involved and what the actual problem is. But I would think it would start from about 5k to resubstrate and resurface.

D1023319

374 posts

Ultimate Geek
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Reply # 744665 14-Jan-2013 17:07

Hi

I agree with Mattwns recommendations to you re 18mm plywood but would suggest you remove the original roof of hardyboard to ensure solid join to roof joists to ensure no movement between sheets.

Rather than bytynol to walk on which is fragile, I suggest you look at "traffic guard" which is designed for this purpose.

http://aquaproofpune.com/fosroc/trafficguardUR150.php

While this link doesnt mention fibreglass - I believe you can include it in the coating.

The biggest issue as Matt says is why the leak where the concrete meets the deck?
Also even if the roof / deck was water tight , where would the water go, e.g. down the walls?

cheers

ventolin

104 posts

Master Geek

Reply # 744666 14-Jan-2013 17:08

Awesome replies guys thanks heaps. The previous owners installed guttering and down pipes onto the side of it.

mattwnz

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Reply # 744668 14-Jan-2013 17:16

ventolin: Awesome replies guys thanks heaps. The previous owners installed guttering and down pipes onto the side of it.

You can possibily get someone in to patch it for a few hundred, but they probably wouldn't guarantee the work. But if you are doing that, I wouldn't enclose it on the underside, because if it leaks again that will cause all sorts of problems with rot. You are probably best to get it done properly if you are enclosed the ceiling.

wellygary

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Reply # 744672 14-Jan-2013 17:22

D1023319: Hi

I agree with Mattwns recommendations to you re 18mm plywood but would suggest you remove the original roof of hardyboard to ensure solid join to roof joists to ensure no movement between sheets.

Any install these days will glue/screw the ply/particleboard to the beams so it shouldn't move, and given it is a deck they will probably also use something like "green tongue which is a tongue and groove system for keeping the edges of panels together...

mattwnz

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Reply # 744677 14-Jan-2013 17:30

wellygary:
D1023319: Hi

I agree with Mattwns recommendations to you re 18mm plywood but would suggest you remove the original roof of hardyboard to ensure solid join to roof joists to ensure no movement between sheets.

Any install these days will glue/screw the ply/particleboard to the beams so it shouldn't move, and given it is a deck they will probably also use something like "green tongue which is a tongue and groove system for keeping the edges of panels together...

They definitely shouldn't be using particle board, which is for interior use only. It has to be ply with H3 or similar treatment, or something else as durable that the membrane manufacturers recommend..

Niel

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Trusted

Reply # 744679 14-Jan-2013 17:31

Not a builder, but would guess you should install plastic sheeting to prevent future leaks from dripping onto the ceiling board. Especially since the roof is a deck which will eventually spring a leak.

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