Tanilised tongue and groove boards

[simon831]

I have been making a number of shed and barn doors.
6x2 for the frame with a rabbit around the middle to take the boards.
Tanilised 3/4" tongue and groove boards glued and brad nailed in place.

A few weeks later the boards on the first doors are starting to separate and split. Sometimes the glue fails and sometimes the tongue splits off. I can't see that I am doing anything massively different to all the youtube videos I watched.

I have more doors to make. Does anyone have any suggestions on how to prevent this on the next door, or even on the seemingly doomed door I made last?

[ayjay]

Have you tried not gluing the T&G?

[dewaltdisney]

T&G will acclimatise to its environment and expand and contract depending on the humidity. It should really be assembled loose but pushed up tight. One thing is to leave the timber in the area it is to be installed to meet the surrounding humidity, cover from rain and keep off the ground. Paint with the finish or preservative all around before assembly so if the boards do move there are no white gaps.

DWD

[Dave54]

As said the boards shouldn't be glued. I wouldn't rebate the boards at the edges either, they're better tongue and grooved in at the stiles and the top rail. The middle and bottom rails use barefaced tenons, and are thinner than the frame by the thickness of the T & G, which runs over them, and is fixed to them either by nailing or screwing with plugs. One fixing per board. The bottom rail is fixed up from the bottom of the door a few inches and the T & G boards run over it to the bottom of the door, they don't sit in a rebate, or have a tongue which would accumulate water and eventually rot.
OP I think you have been watching American videos on YouTube. Their joinery methods are quite different from ours in the UK. They have different weather in most parts.

[big-all]

yes never glue
smaller boards say ex5" about 109mm coverage will be more stable
basically iff you glue it it must be sealed it to stop water penetration [paint]
if its open to the elements it needs room in the construction to move

[Hitch]

Board's probably a bit damp from the off too I imagine. Start off big, then shrink back as they dry.
Plus panels in frames shouldn't really be glued.