T&G headliner falling off

[Kismet]

Hello, 

I have a Tounge and groove headlining in my 40’ narrow boat. I haven’t been to see it for two months due to covid but just came to check on it and the tounge and groove has fallen apart, see photo. In winter it was bulging a bit which I assume was due to moisture and maybe now it has shrunk in the heat causing this? Is there a way to fix it without taking it all out, can I nail back into the horizontal battens or would that be stupid? 
thanks in advance. 
Hannah 

[David Schweizer]

29 minutes ago, Kismet said:

Hello, 

I have a Tounge and groove headlining in my 40’ narrow boat. I haven’t been to see it for two months due to covid but just came to check on it and the tounge and groove has fallen apart, see photo. In winter it was bulging a bit which I assume was due to moisture and maybe now it has shrunk in the heat causing this? Is there a way to fix it without taking it all out, can I nail back into the horizontal battens or would that be stupid? 
thanks in advance. 
Hannah 

My advice is to initially try and push it back together, and hold it back in place using fine nails pinned into the roof battens, leaving the heads protruding for easy removal after the panels have expanded. One issue is that I cannot see any roof battens, which may be part of the problem, in which case you may need to temporarily hold the boards into place with long pieces of wood. Long term you may need to fix each board using screws (which can be removed easily for access) and tolerate the summer gaps in the future.  One small advantage you have is that the tongue and grove is actually matchboard, which has a chamfer on each edge which is designed to help visually conceal contraction gaps.

[Movin' on]

You might find if there are inadequate fixings behind it that you will have to put a couple of cross braces (6-8ft spacing) on the surface to hold it together - if you did these in a quality contrasting wood strip to match the walls (tip - always buy a bit heavier/thicker than you think) they would add more character and look perfectly OK - that would completely solve the problem as you could fix them together as one .................

 

Edited June 3, 2020 by Halsey

[BEngo]

The t&g appears to have dried out, in the recent warm spell no doubt, and has shrunk so the grooves are not supported by the adjacent pieces tongues. It will probably grow larger when it starts raining again.

Depending what is fastened to, Gripfill or similar may be your friend.  You will need to prop the t&g up while it sets  but the green tube Gripfill goes off really quickly.

N

 

[David Mack]

And you need to sort it now before we get into damper weather (it is drizzling here as I write, for the first time in weeks), otherwise you won't be able to get the tongues back in the grooves.

[Onewheeler]

It looks as if there are no (or few) supports above it. T&G moves, but it looks as if all of the movement has been between two sections. Possible that the lengths were glued and it's failed at the weakest joint?

 

The easiest solution as others have said is to put braces underneath the T&G running from side to side and screw against the T&G. Something roughly 35 mm x 12 mm? You can get timber with a chamfer on both sides so there won't be sharp edges to bang your head on. Ideally cut to the brace to length so that that both sides are fixed securely to the sides of the cabin and bent to accomodate the curvature of the ceiling (which doesn't look very curvy).

[system 4-50]

Is there any insulation up there? Or is the T&G cooking in hot weather?

[Kismet]

On 03/06/2020 at 15:53, Onewheeler said:

It looks as if there are no (or few) supports above it. T&G moves, but it looks as if all of the movement has been between two sections. Possible that the lengths were glued and it's failed at the weakest joint?

 

The easiest solution as others have said is to put braces underneath the T&G running from side to side and screw against the T&G. Something roughly 35 mm x 12 mm? You can get timber with a chamfer on both sides so there won't be sharp edges to bang your head on. Ideally cut to the brace to length so that that both sides are fixed securely to the sides of the cabin and bent to accomodate the curvature of the ceiling (which doesn't look very curvy).

I’ve had a look at there are a few supports and putting my hand in I can feal nails that are still in the panelling but not connected to supports... thanks for the advice this sounds like a good plan! 

On 03/06/2020 at 16:39, system 4-50 said:

Is there any insulation up there? Or is the T&G cooking in hot weather?

Yup there’s poly styrene (throughout the whole boat) that one day I was planning on upgrading ... just haven’t got there yet! 

Thanks everyone for the replies really helpful! 

[Bee]

What I would do (not always the best thing) Get some panel pins. pin it back up as best you can with PVA glue where the back of the matchboarding touches the battens and it should stay put, then if the gaps are reasonable get some decorators caulk from B&Q or somewhere and a cheap 'gun' and fill the gaps. (Wipe it smooth with a damp cloth) Wood is awful stuff for shrinking and swelling and a Good Tip is to paint the back of the stuff before it goes up otherwise it 'cups', i.e. goes concave .  If I ever do another boat it will be made of plastic or brick 'cos my boat has all sorts of gaps/splits/cracks.

[Murflynn]

2 hours ago, Bee said:

What I would do (not always the best thing) Get some panel pins. pin it back up as best you can with PVA glue where the back of the matchboarding touches the battens and it should stay put, then if the gaps are reasonable get some decorators caulk from B&Q or somewhere and a cheap 'gun' and fill the gaps. (Wipe it smooth with a damp cloth) Wood is awful stuff for shrinking and swelling and a Good Tip is to paint the back of the stuff before it goes up otherwise it 'cups', i.e. goes concave .  If I ever do another boat it will be made of plastic or brick 'cos my boat has all sorts of gaps/splits/cracks.

T&G will always want to move, that is the beauty of the joint design - it allows movement.  How is caulk going to help?  IMHO it will look a mess if you put any type of goo in/over the joints.

 

I agree with others that the only satisfactory cure is to add cross supports at regular intervals (coinciding with the existing battens above the T&G?).  These permanent support battens should be selected timber, preferably hardwood or else selected seasoned pine.  I would go for something about 50x12.  

Before you start try to locate every existing batten and mark the positions on the T&G. 

I would start by installing strong temporary battens (say 75x22 whitewood) supported by some cheap struts (I always use 3x2 CLS for jobs like that) propped off the floor and wedged to force the T&G back into position.  It will require a bit of tapping here and there to get it back as best you can. 

Once everything is in place neatly install the permanent battens, screwed through to the existing battens, one screw through each board.  You can get domed head wood-screws that could be used as a feature, to avoid having to countersink and make over every screw-head. 

Do not glue anything - allow the boarding to move, subject only to the constraints of the screws.  

Remove the props and repaint.

Edited June 5, 2020 by Murflynn