How to fix my conservatory!
April 5, 2011 9:26 AM Subscribe
We have just removed some wooden floorboards from our conservatory - there is a leak from somewhere that has caused the floorboards and the 2x3 to rot. Can anyone help identify and recommend a way to fix this?
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The concrete floor has small trenches where we can see water is draining from but it looks like either they have placed the 2x3 too close to the trench or water is traveling along the wood from the stone stairs.
In addition, there was a long piece of wood wedged into the gap (shown in Image4) that was very wet.
I am trying to decide wether it would be best to fill the gaps in the stone stairs with expanding foam / cement or if there is an alternative explanation / option.
The concrete floor has small trenches where we can see water is draining from but it looks like either they have placed the 2x3 too close to the trench or water is traveling along the wood from the stone stairs.
In addition, there was a long piece of wood wedged into the gap (shown in Image4) that was very wet.
I am trying to decide wether it would be best to fill the gaps in the stone stairs with expanding foam / cement or if there is an alternative explanation / option.
Best answer: You need to sort out just what all the drainage is doing there. You need to reroute any drainage that is getting into that and if you can't you need to install a wet well with a sump pump. Moisture control is the key piece of most construction. If you can keep it dry and allow air to circulate you generally would have any problems with rot or mold. If water is accumulating faster than it can evaporate or drain away you will have problems.
A few more observations:
Concrete is not waterproof. It is quite pourous actually and will rot any wood in contact with it.
It appears that it isn't even lumber down there but a product called OSB. This stuff can't take any moisture and should only be used as sheething material for walls and such in well ventilated construction. It is particularly suitable for high pitched roof sheething as long as you have good vents. It is not ok for use agaisnt concrete no matter how well vented it is.
You have a drainage pipe and channel in this area. You need to reroute that or use some form of concrete/concrete block construction to build anything down in this. You really need 18" or more of clear air space between anything that is saturated and wood, or use a membrane and treated wood.
This might be one you need to get a contractor in on to sort out. It looks complicated.
posted by bartonlong at 10:04 AM on April 5, 2011 [1 favorite]
A few more observations:
Concrete is not waterproof. It is quite pourous actually and will rot any wood in contact with it.
It appears that it isn't even lumber down there but a product called OSB. This stuff can't take any moisture and should only be used as sheething material for walls and such in well ventilated construction. It is particularly suitable for high pitched roof sheething as long as you have good vents. It is not ok for use agaisnt concrete no matter how well vented it is.
You have a drainage pipe and channel in this area. You need to reroute that or use some form of concrete/concrete block construction to build anything down in this. You really need 18" or more of clear air space between anything that is saturated and wood, or use a membrane and treated wood.
This might be one you need to get a contractor in on to sort out. It looks complicated.
posted by bartonlong at 10:04 AM on April 5, 2011 [1 favorite]
Best answer: Sort out the source of the water and solve that before performing any other fix.
Everyone above is spot-on.
posted by jbenben at 11:33 AM on April 5, 2011
Everyone above is spot-on.
posted by jbenben at 11:33 AM on April 5, 2011
Best answer: Yeah, you're going to want to rip out all the OSB. It won't last very long anyway. This is a perfect time to redo the whole mess up to modern standards. A concrete-floored conservatory, especially if attached to your house (?), should probably be handled essentially like a basement remodel. You're in luck because there are many fairly new products and approaches nowadays, whereas it looks like what you have was built sort of as a hack.
One guess for the rot around the stairs is that you have moisture seepage coming up through whatever makes that corner structurally different; another is that that corner has settled and moisture naturally collects there. Either way, this is something you need to solve. The channels actually suggest a primitive way to drain the area, meaning there was always a problem and it just wasn't dealt with.
Moisture in a basement is something you deal with by stopping as much getting in as possible first. This can mean grading outside to make sure water off the roof/gutter system gets away from the building, and adding things like dry wells, french drains, or moisture barriers on the outside of the foundation. If it's still getting inside, or you can't do any of that for whatever reason, you're essentially conceding that you've lost a battle and you have to just mitigate what's getting in. Sump pumps and a properly laid floor with properly draining channels, typically along the outside wall, can be part of that. But in a situation like that you really don't want to casually finish out a floor with substandard materials.
There are a number of good books on finished basements; I highly recommend anything from Taunton Press, including these Fine Homebuilding articles or the book Build Like a Pro: Remodeling a Basement.
posted by dhartung at 1:20 PM on April 5, 2011
One guess for the rot around the stairs is that you have moisture seepage coming up through whatever makes that corner structurally different; another is that that corner has settled and moisture naturally collects there. Either way, this is something you need to solve. The channels actually suggest a primitive way to drain the area, meaning there was always a problem and it just wasn't dealt with.
Moisture in a basement is something you deal with by stopping as much getting in as possible first. This can mean grading outside to make sure water off the roof/gutter system gets away from the building, and adding things like dry wells, french drains, or moisture barriers on the outside of the foundation. If it's still getting inside, or you can't do any of that for whatever reason, you're essentially conceding that you've lost a battle and you have to just mitigate what's getting in. Sump pumps and a properly laid floor with properly draining channels, typically along the outside wall, can be part of that. But in a situation like that you really don't want to casually finish out a floor with substandard materials.
There are a number of good books on finished basements; I highly recommend anything from Taunton Press, including these Fine Homebuilding articles or the book Build Like a Pro: Remodeling a Basement.
posted by dhartung at 1:20 PM on April 5, 2011
Response by poster: Hi everyone,
Thank you for taking the time to explain and offer your solutions. We're cracking on with getting the conservatory fixed now - just surprised how much of a cowboy job it was in the first place!
Many thanks!
posted by SRMorris at 11:48 AM on April 6, 2011
Thank you for taking the time to explain and offer your solutions. We're cracking on with getting the conservatory fixed now - just surprised how much of a cowboy job it was in the first place!
Many thanks!
posted by SRMorris at 11:48 AM on April 6, 2011
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What you need, before building up the floor again, is one or another kind of membrane with distance holders that allows the concrete to breathe while it protects the floor above. Like this, for instance.
posted by Namlit at 9:41 AM on April 5, 2011 [2 favorites]