Shiplap Cladding Leaking badly

[jeni2]

I have had an office/sumerhouse built from scratch. Pretreated Redwood shiplap cladding 19mm thick was used inside and outside with a layer of insulation inbetween. I coated the outside using a stain preservative and folllowing the wet summer we have had all the walls are now leaking like a sieve. I have no idea why this should be. My neighbour put up a simple shed and he has no leaks.I would appreciate any thoughts, advice or suggestions.
Thanks

 

[JohnD]

did you put the boards in upside down? No other reason why it should leak like a sieve

If however it is leaking from a limited number of points, tell us where they are. If you pull back the insulation you will see where it is getting in. Maybe it is the detailing where the roof meets the walls.

p.s. timber cladding is never perfectly weatherproof. My shiplap is on battens on felt.

 

[jeni2]

Thanks for your reply. My joiner built it and it is the shiplap (log cabin look) so not sure if that can be put in upside down. It appears to be leaking where each piece of wood is locked into the other and then it travels down the batton to the floor and then comes out in a puddle at the bottom. There is no lining and it is the itchy insulation that has been used. My joiner seems to think if i use a much better quality preservative on the outside that will sort the problem but I am not so sure.

 

[big-all]

are you talking top and bottom off the boards or ends butted up together!!!

 

[JohnD]

preservative will not seal leaks

photos would be nice, especially showing the ends of the timbers.

the log stuff is not shiplap.

 

[Deluks]

Was asked to look at a similar structure this week. Despite the shiplap being old and warped it turned out to be the roof that was leaking into the cavity. Felt had a few holes that weren't visible until you climbed up there. Does yours have guttering?

 

[jeni2]

It is at the top and bottom of each piece of wood where they slot in to each other. I have taken some photos and will try to upload them. They are perhaps not that clear as it has stopped raining and my joiner has temporarily put some plastic over the back of the building to stop the water getting in. The photos are only really showing the dampness at the bottom but if you put your hand behind the insulation the boards are very wet. Whether this is through penetration or if the water is getting in at the seal and then trickling down the back...i am not sure. Only some of the boards seem to be affected. The roof is sound I really don't think it has anything to do with the roof. If you need more photos please let me know.
Thanks to all who reply appreciate your advice.

 

[big-all]

i used cuprinol a very waxy one that stops penetration cant remember what its called this should stop water getting through small gaps due to surface tension

once the water soaks in the smaller gaps attract water through cappilery action

 

[jeni2]

As no-one has come back to me with any advice or solutions i am guessing there is no simple solution. I have uploaded 5 photos but have no idea if this will help. Thanks to all who replied.

 

[Chukka63]

its hard to comment without the pics.where have you posted the pics???

 

[lordgoata]

its hard to comment without the pics.where have you posted the pics???

//www.diynot.com/network/jeni2/albums/4173

 

[big-all]

As no-one has come back to me with any advice or solutions i am guessing there is no simple solution. I have uploaded 5 photos but have no idea if this will help. Thanks to all who replied.

did you read my post before yours!!!

i used cuprinol a very waxy one that stops penetration cant remember what its called this should stop water getting through small gaps due to surface tension

once the water soaks in the smaller gaps attract water through cappilery action

 

[jeni2]

I did read your post, thanks. Although what you say may be correct, i just thought it may be being caused due to some other reason. The company who sold me the wood state that it is due to condensation caused by the insulation inbetween. Again I'm not entirely convinced by that. I think Big Al you may well have a point as I notice water is only coming in in certain areas like corners etc since my joiner has now covered the outside of one wall and the area is drying beautifuly inside, (so that bombs out the condensation theory.) I think the wood is Redwood Pine and I presume this wood is ok for building sheds etc.

If i use a high quality waxy preservative is this all i need to do. Would it be worth putting some form of silicone sealant in the leaky areas or not? I think you should be able to get the photos by clicking on the link below. If not I have no idea how you acess them. I have uploaded them and they are in my album .
//www.diynot.com/network/jeni2/albums/4173

 

[ratman123]

No cavity, no membrane, pretty much what i would expect to happen.

You can lather on sealants and mastics to all the joints, particularly the corners, it may work, but will need ongoing maintenence. Where possible a timber coverplate with drainage grooves will work better than mastic.

 

[big-all]

i gave my shed 3 good coat and plan to recoat with 2 or 3 coats every 5 years or so

and as ratman says you must always have a membrane and an air gap

now you can take a risk like i have as long as your at least 99% shure you have cured the leaks you can take the chance whack in insulation and board with ply

if you do get moistre trapped it will eventualy discolour the ply with stain or mold if that happens you will have to expose that area and remedy the problem

when i built my shed at the corners i overlapped the corners by 9 to 12mm so the rain would have to go round a corner to reach the end grain
so iff you imagine a bit off 2x1 treated with a rebate in one end and a rebate at the other end but at 90 %

i wouldn use white silicon if you have to use use clear as it wont takestain or finnish

http://s21.photobucket.com/albums/b270/bigall2005/

my shed before the 3 layers of torch on felt or 3 coats off treatment
also before the insulation and 12mm ply cladding