Single glaze - leaking frame, rotten membrane

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grahamhowe

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Topic # 150060 10-Jul-2014 09:01

Hello, I'm looking for advice from those with experience or are in similar situation where your aluminum framed single glaze windows have leaked and the wood wall membrane has gone rotten somewhat. I have attached photos. My issue is thus, when I removed the rotten wood membrane to then replace it I found the outer underside of the window frame to be sweating with condensation on the colder days which from what I could see could be why the wood membrane was rotten? Does this mean that the whole window frame could be 'sweating' and the wood frame holding the window frame is also rotten, from what I can see, the wood membrane around the window is exposed, I can't see any other rot. I'm now thinking it's because the window frame is now exposed to the air and it then sweats.

What are your thoughts? Before I replace the wood I'd like to know if I need to take the window out and line 'insulate' the wood from the aluminum window frame.

Thanks in advance.

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Reply # 1086235 10-Jul-2014 09:18

To help with other replies I'd suggest a wider shot showing all of the framing below the window and a definition of what you're calling the "membrane".

grahamhowe

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Reply # 1086241 10-Jul-2014 09:21

Oh, I thought 'membrane' was builders speak for the wood frame that makes up the wall, this is what I mean by membrane is the wood framing wall :-)

I will post a wider shot of the windows this evening. The only rot is in this corner as per the photographs but yes you're right I'll offer more context.

Back soon. Thanks.

timmmay

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Reply # 1086278 10-Jul-2014 10:06

I don't think it's called a membrane.

I suggest you get a builder in to replace the framing, fingers crossed you can reuse the window.

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Glassboy

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Reply # 1086286 10-Jul-2014 10:31

grahamhowe: Oh, I thought 'membrane' was builders speak for the wood frame that makes up the wall, this is what I mean by membrane is the wood framing wall :-)

I will post a wider shot of the windows this evening. The only rot is in this corner as per the photographs but yes you're right I'll offer more context.

Back soon. Thanks.

In this context I think you're meaning a moisture proof material that goes under the external cladding. See section 5.1 here http://www.dbh.govt.nz/UserFiles/File/Publications/WHRS/pdf/constructing-cavities.pdf

wellygary

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Reply # 1086288 10-Jul-2014 10:43

Glassboy:In this context I think you're meaning a moisture proof material that goes under the external cladding.

And which by the look of these photos does not appear to exist ( I am assuming the "white" is some sort of firbrelite panel/sheet.

The reason the wood is rotting is because there is no "membrane" between the window frame and the exterior caldding, (From memory today they would lap the membrane into the bottom of the windows void and then insert the window frame, so any run off from the window is kept away from the framing,

You will need to take the whole window out, replace the surrounding rotten joists and then re affix the window frame to the new framing,

I'm guessing that the timber is all laser frame or otherwise untreated, hence the rot, you will need to replace it with H1.2

grahamhowe

8 posts

Wannabe Geek

Reply # 1086292 10-Jul-2014 10:56

Cheers WellyGary. Thats my thoughts too as per the building code seen in new builds to encase the space where the window is being fitting with the membrane. The cladding is exposed as the builders paper has eroded away so I'll then need to renew that, oh and whilst on the job I should re-clad the whole house with proper weatherboarding instead of this 80's fibre cement boarding.

Thanks folks. Much work to be done.

P.S. My father's coming over for his hols this xmas and he's a builder. I'll remind him to bring his tool belt.

RunningMan

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Reply # 1086297 10-Jul-2014 11:01

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grahamhowe: [snip] I should re-clad the whole house with proper weatherboarding instead of this 80's fibre cement boarding.

Be careful that isn't an asbestos product - if it is, don't touch it, and get in a company that specifically deals with asbestos removal.

Bung

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Reply # 1086310 10-Jul-2014 11:17

Something seems wrong with the detail below the window where there seems to be some sort of flashing. Was there another piece of horizontal framing forming the sill that has been chopped out? This describes current practice http://www.branz.co.nz/cms_show_download.php?id=dd0bd80c737c9ebf49722dfa128c1db247264ea4

I have had a similar problem with a wooden window where water was leaking past some rusty nails in the central stile. Taping the still framing was well worth it.

Think carefully about changing too much. Changing to weatherboard will mean a building consent and that may lead to having "cavity" fixed rather than direct fixed as you currently have. This will affect all your windows etc.

grahamhowe

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Reply # 1086312 10-Jul-2014 11:22

@Bung. Yes I've chopped out the rotten wood and I'm replacing it with treated framing. I stopped work because of the condensation I spotted on the underside of the window frame and then thought it might be like this all around the frame on colder days and so turned to this great forum, by the way thanks to ALL :-)

No cavity is an issue and yes I was joking about the re-cladding job. I will however when I inspect the insulation in the walls inside the house I will be removing the jib and inspecting the framing around the windows elsewhere in the house.

I think the 'taping' or using installing a membrane around this window will help. Should be interesting removing the window.

My foreman is a father via Skype.

Bung

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Reply # 1086317 10-Jul-2014 11:30

Try a pm to gazbo, he adds value to this sort of thread.

Fred99

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Reply # 1086696 10-Jul-2014 20:01

I suggest you get an aluminium joinery / repair company to look at the windows. Whether condensation or leaking, there may be a preventative fix for the other windows without removing them.
For example here : http://www.exceed.co.nz/maintenance/services/windows-repairs-faults/
The cladding without cavity is a bit of a concern. You might be able to get an idea of damp problems from inside - moisture test on the gib, but that may not answer whether it's getting through the cladding etc or there are problems with other windows. You do need to get this sorted.

gzt

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Reply # 1086702 10-Jul-2014 20:11

wellygary: The reason the wood is rotting is because there is no "membrane" between the window frame and the exterior caldding

Very unlikely. Many older houses used similar construction methods and do not have rot around the windows from condensation. It is far more likely there is a minor issue somewhere which is allowing a fair drip of moisture into the cavity every time it rains. Some wider photos are required to educated guess at where that might be. Could be the window itself but there are many other possibilities. For instance a nail worked out of it's hole in the external cladding in exactly the wrong place can be the cause of things like this if left for a few years.

Fred99

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Reply # 1086902 11-Jul-2014 08:39

gzt:
wellygary: The reason the wood is rotting is because there is no "membrane" between the window frame and the exterior caldding

Very unlikely. Many older houses used similar construction methods and do not have rot around the windows from condensation. It is far more likely there is a minor issue somewhere which is allowing a fair drip of moisture into the cavity every time it rains. Some wider photos are required to educated guess at where that might be. Could be the window itself but there are many other possibilities. For instance a nail worked out of it's hole in the external cladding in exactly the wrong place can be the cause of things like this if left for a few years.

From the look of those photo there isn't a cavity. While cladding might have been direct attached to framing in the past, it might have more likely been packed out to mount cladding flush on to (uneven) framing. The OP's example has multiple problems. The window design / flashing system is apparently inadequate. If water gets in anywhere - window, nail hole or elsewhere, then not only is there nothing to stop it from getting in to the framing, but because the cladding is direct attached, there's no air circulation to dry it out, and there are also no gaps between horizontal dwangs etc and the cladding - so any water which does get in is trapped. As to whether the cladding is asbestos - then hopefully not - but it needs to be tested.
It won't be what the OP wants to hear, but that's classic "leaky home" failure - and the best way to fix it would be to re-clad bringing it up to code, probably at the same time replacing all the window joinery and insulating exterior walls.

Bung

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Reply # 1086917 11-Jul-2014 09:14

If its a ground floor window maybe a shot of the outside as well as the wider view inside. What looks like a sill flashing doesn't seem to have much cover over the top of the fibro sheet. If it is a mid to late 80s build it is likely to be the newer asbestos free sheeting that had cellulose fibres instead. I think it got treated like the old fibrolite that could be left unpainted but it should have had edges sealed to stop it absorbing water. On our 86 bach anything covered missed getting paint. I've taken some sheets off to redo the building paper. The good thing is the framing shows no sign of rot or mould even where there's been some dampness.

grahamhowe

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Wannabe Geek

Reply # 1086924 11-Jul-2014 09:21

Thanks further for contributing. I will add further exploration photos this weekend. I have since moving in sealed the outer top and sides (not underneath) of the window frame; no further leaks have appeared so I'm thinking this happened post to us moving in. Thank you previous owner. The window seal is then in question.

Re the cladding this fibre cement cladding has no cavity and isn't nailed to the frame except the very last row on the building which is nailed to stop it flapping in the wind. These nails I have since sealed. I'm getting on top of these little issues.
Because of the window leak the builders paper has detoriated so it will need replacing because I want to install wall insulation.

photos coming soon. Thanks folks.

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