T&G ship lap cladding question

[blades]

Just wondered if anyone had any thoughts / solutions to a problem I currently have?

 

I have a building clad in 19mm T&G cladding (similar to the pic) one of the gable ends seems to leak along the joins. The joins are tight and the timbers has been treated with cuprinol garden shades (2 coats). I have checked the roof and feel confident no water is entering here. The roof is sarking on top of trusses, roof shield, perlins and steel roofing sheets.

 

Feeling a bit stumped to be honest

 

Thanks in advance for any advice

[Graham S]

Run silicone over some of the joints and paint over .

[Woodworks]

I don't think water could get in through the tongue so if it is coming in through the boarding it must be were the ends butt up to each other. I would guess that this on the end exposed to the prevailing winds. The Cuprinol garden shades finish is it a penetrative preserver of does it have some surface build up? The only other thought is there is a knot or two that are loose letting water in. I am presuming this is on your new supper shed so hope you find the problem and can fix it as that shed is a thing of envy.

 

If you put silicon on no finish will ever stick to it.

[Kennedy]

I've been having the same problem with a shed I recently built. I used 150mm larch boards run horizontally and overlapped them by 30mm and its as if the water is soaking up the wood then through into the shed, my only plan is to use an oil based treatment to try and solve the problem

[Graham]

If it's on the side facing the weather then the wind could be forcing the rain into the joints and along with capillary action it's getting through.

 

Were the boards slightly damp when it was built? I built a stable once using shiplap cladding and the boards shrank slightly as they dried allowing rain to be forced in with the wind.

[blades]

Thanks guys.... The cuprinol shades seems to put what almost looks like a thin plastic coating over the timber.... To my eye when I look close up to the joints they look sealed

 

Believe it or not the gable end with the problem is quite well protected being only 4 metres away from tall dense hedging which itself is about 5m thick.

The other gable end totally exposed seems fine?

 

This is the building... It's the gable end to the left in this picture

[Stu3k]

give exterior sadolin a try

[blades]

give exterior sadolin a try

 

Checked their website.... It doesn't read as if it could go over the 'shades' coating I have used already??

 

Do you know if it can go over another treatment ok?

Edited February 3, 2013 by blades

[Woodworks]

Not the new shed than.

From what you have said I am presuming that there is no breathable membrane behind the cladding. On a building like that I would have expected one. Is it much water or just a little dribble? You may always get a small amount through where the ends meet. This would not really mean anything on an open barn or shed but on a building like that I can see your problem. I would apply more of the same finish paying special attention on the joins and hope for the best. I know you are pretty sure it is not the roof but is there any chance rain is blowing under the edge flashing and then dribbling down inside. If it was that it is an easy fix with a line of mastic tape applied between the last ridge of the roofing sheet and the underside of the flashing.

[agg221]

Are you absolutely certain its not condensation on the inside of the roof which is then running down? Does it show wet from top to bottom, and across the full width, or is it localised?

 

If you're prepared to overcoat afterwards, you could try a bottle of food colouring or water-based ink, applied strategically (e.g. on the outsides where you think water is coming through) and see if you get traces on the inside. This will give clear indication as to where the water is penetrating.

 

Alec