Newbie: Sealing gap between cladding boards on shed

[crlong]

Hi all,

I am a reluctant DIYer who is in need of regular advice and encouragement.

I have a shed that is clad with shiplap (not T&G) pine. Where some boards butt joint, water got through in the recent rain. After the fact, I am told that roofing felt between the butt would have made a good sealant. I have raked out the gap between the boards and "injected" and "pushed in" frame sealant. However, I am concerned this sealant isn't very deep and won't repel future rain. If the cladding was flat I could fix wooden battens over the butt joints, unsightly but effective. So I am thinking if I can stick some kind of "flashing" over the joints this might make them weather proof. I have used "self-adhesive" bituminous flashing for cracks in roof felt in the past - and very effective it has been - but most of the surface was horizontal. On the shed wall cladding the surface is completely vertical, not flat and painted. I have also thought of getting some kind of flexible tape and using frame sealant to fix over the butt joint. The cosmetics aren't too vital as the problem joints are at the back of the shed and not visible and I can paint over the joints.

Any suggestions on materials or other approaches to make the joints water-tight? Currently the weather is dry but I have heavy duty plastic sheeting over the back which has been effective at keeping out the rain. Eventually I want to remove the sheeting.

Thanks,

Clive

 

[Sombrero]

I'm a DIYer too... and I'll give you a starter for 10... the pro's will then pile in...

A shed covered in ship lap should do exactly that, and "lap" over the board beneath it. Water will splash, but not run or pour upwards, so a sufficient over"lap" of about half an inch (10mm) should be fine - admitted some wany edged timber is all over the place.

Using frame sealant on shiplap timber is a huge mistake in my book.

A waterproof sheet between shed and covering would help, but might compromise the back of the covering timber.

A decent waterproof stain would be useful?

Sheds are pretty simple things, so you should find a simple solution... good luck !