After some years of the shed being built I have got full access to the back, on the whole it is in good condition, well nothing a good couple of coats of oil wont fix. but there is 2 sections were the shiplap had cupped and the tongue and grove have separated for about 3 feet and as it is in the middle of an 18" run, is there any way of of pulling it back in? I thought about some screws and washers and over the next few weeks gently tightening the the screws to try and get it back in place.