Shiplap (cont) problem...

[Thermo]

aha, a picture doesnt tell a thousand words. ok rules that one out then!

 

[masona]

Hmmm, it does look like the rain coming though the nail head internally on pic 20 and I think one of the reason I haven't had any problem because I use the fixing inside only. Maybe you can try a give the nails head another coat of tung oil.

 

[gord55]

The "drip" on a shiplap board is not strictly a drip... water will run back against the face of the board below & then go through the "joint" by capillary action, which is why I said earlier that I don't think you'll ever stop it leaking completely. The best you can do is to prevent the water reaching the inside walls of your shed (which is why you'll need a water barrier).

A drip should always overhang, giving the water a large gap to cross - like the bottom edge of a fascia board, or the large groove under a cill. The whole point is to stop water ruuning back along the horizontal surface... and a shiplap board, being butted tightly against the board below, does not allow the water to "drip" off, just to run down the face.

Trust me, I'm a cowboy.

 

[masona]

Yep, that why I wanted to see the end grain of the shiplap. The way round it is to planed the drip 45 degree angle which will push the rain away from the top of the shiplap underneath.

 

[gord55]

Yes, that'll do nicely. I don't know why manufacturers don't do that anyway - I've never seen shiplap with a bevelled bottom edge. I guess if there's only 10mm or so cover, a 45° bevel wouldn't leave much to overlap...

 

[petewood]

, which is why I said earlier that I don't think you'll ever stop it leaking completely..

I can't understand this. I have made dozens of sheds, stables, playhouses, barns, summerhouses and a farm shop with shiplap and apart from one where the timber was fitted much too wet and shrunk in a major way, I have never been aware of any leakage problem. I suppose it's possible that there was some leakage but on the unlined sheds it was so minimal that I never noticed it and that on the lined sheds I wouldn't have been able to spot it.

I have never used silicone to seal my joints and have never oiled the timber but have always used tanalised softwood and apart from eventually replacing roof-felt and the occasional window there have never been any problems.

 

[big-all]

i am wondering if its just shiplap he is useing and we are talking treated txg shiplap which is weather proof apart from bad fitting and shrinkage!!!!!!

 

[Thermo]

it shouldnt leak at the joints full stop, its designed that way to prevent that. it shouldnt need silicone as you say petewood

 

[big-all]

it shouldnt leak at the joints full stop, its designed that way to prevent that. it shouldnt need silicone as you say petewood

mmmm i agree entirely thermo

but we have two choices here the man removes all the cladding air dries it and refits it after 5 or six weeks !!!!!
or tries to make the best off a incorrect instalment

dont think the first option is on the cards so no 2 and and try and make it work

 

[Thermo]

thing is from the pictures it looks correctly installed as there dont seem to be any gaps. thats why im still suspicious of the fixings. the water can find the minutest hole to penetrate and spread.

 

[ellal]

Ive uploaded a pic of the shiplap profile
(image - shed24) Here

There are a few gaps (horizontal) when the wood is dry, but no more than about 1mm (definately no more than 2mm anywhere), and the water doesn't neccesarily come through in those areas.

I must have made an error somewhere in the construction, but have followed the comments, and still can't work out where..

 

[big-all]

thing is from the pictures it looks correctly installed as there dont seem to be any gaps. thats why im still suspicious of the fixings. the water can find the minutest hole to penetrate and spread.

ok another train of thought here

does tounge oil soak in very far!!!!!!!

my thoughts here
wood a bit to wet when installed wood treated tounge oil dries wood shrinks a few mm leaving a thin band of untreated wood that water can penetrate!!!! and as we know once water finds a path it usualy takes it again
so even though the gap has closed up again with the rain the water has already chosen that path and will use it again

possible solution if my theory is correct

leave the wood till next summer and treat well when its shrunk paying particular attencion to the joins

 

[masona]

Right, the way I'm seeing it, the drip is square and not bevel therefore the rain water suck up inside because of the bare wood not being treated and because of wind pressure or timber expansion pushing the water upward. Might be an idea if you can carefully lever the bottom drip with a flat bar or a thin plastic wedge they use for laminated flooring (might be easier to push it out slightly from inside) and brush it in with tung oil underneath from outside. In the real world the square drip should be angle or bevel.

 

[Thermo]

what are you planing to do with the inside face of the timber, cover it or leave it bare?

 

[ellal]

I think that the general concensus is that there's not a lot I can do until after winter..The vac treatment should protect the shiplap over the short term, even if some water does get through. The framework has 3 coats of preservative, so that should be OK too..

So, when the boards have dried out next year, I'll remove them, and go down the route of putting felt onto the frame, battons of 12x50, and then re-fix the shiplap after giving the inside surfaces a couple of coats of tung oil..(I've measured up, and the window frames will be unaffected, and the door frame will just move outwards by 1cm..)

that'll leave me free to fit the interior OSB3 boards, and kit out the inside, so I can get all my tools/materials out of the house, so I can attack the downstairs rooms this winter!!..

I may also try brushing in the tung oil under the bottom drip as suggested...

does this sound the best plan of action at the present time?