New narrowboat ceiling ceiling fit out has warped and bulged

[Adam1991]

Hi,

 

we have recently fitted our narrowboat ceiling with 5.5mm plywood panels.

 

They were a very snug fit when fitted around 6 months ago. We fixed the plywood using screws and glue onto batons. We have since had to tear the roof down due to bulging and sagging. 

 

We've realised that we may not have had enough roof batons to join to and also did not create an air gap around the plywood. We're seeking some advice on our re-installation of the ceiling.  

 

Should we go for 5.5mm or 9mm boards next time?

 

Plywood or waterproof MDF? 

 

What is the ideal air gap around the chosen material? 

 

We hadn't yet drilled holes for the the LEDs and mushroom vents, could this have contributed to swelling due to moisture build up on the underside?

 

Any advice on the fixing method - ie how much glue to apply and where?

 

Thanks,

Adam

 

 

[mrsmelly]

Whatever you end up doing, ensure you dont butt anything up to anything else. Remember Steel heats up and expands at a different rate to wood. Everything moves about at different rates. In winter wood can swell a little and if no room to expand then they will bulge and buckle. I would never use mdf, others would disagree though.

[Tracy D'arth]

Did you varnish the back before fixing? You should.  Is there condensation on the roof? Battens at 18" centres longitudinally? What glue? Evo Polyurethane foaming 5 minute gun glue is best for working overhead.

 

MDF has no place on a boat.

[David Mack]

What insulation have you got? Was there any water staining on the plywood? What is the spacing between the battens?

In any event 5.5mm plywood is pretty thin for this application. Might be OK if it's good quality multiply, but cheap DIY shed ply with two thin face veneers and a relatively thick single core ply, is not really up to it.

[MtB]

Point of Order if I may M'Lud....

 

On a boat I think its called a "deck head", rather than a ceiling.

[OldGoat]

4 hours ago, MtB said:

Point of Order if I may M'Lud....

 

On a boat I think its called a "deck head", rather than a ceiling.

Pedant! - but sadly out of time in today's boating world, where boats anre becoming more of residences that umm - boats...

[chevron]

We used pvc not everyone’s taste but cheap no painting, warp or damp problems. Been up six years and it has been perfect for us.

[Tracy D'arth]

Glossy!

 

Who are you calling a deck head?

[MtB]

36 minutes ago, chevron said:

We used pvc not everyone’s taste but cheap no painting, warp or damp problems. Been up six years and it has been perfect for us.

 

 

Is that a loft hatch in the middle??

 

 

[cuthound]

5 minutes ago, MtB said:

 

 

Is that a loft hatch in the middle??

 

 

 

Some people want all the comforts of home on their boats... 😂

[swift1894]

22 hours ago, MtB said:

Point of Order if I may M'Lud....

 

On a boat I think its called a "deck head", rather than a ceiling.

Correct. Also the ceiling is actually the cabin side. Unfortunately traditional boat terms are dying out amongst boaters as well as those who just live on a boat cos it’s cheaper accommodation.

Edited February 6, 2022 by swift1894

[Laurie Booth]

22 hours ago, MtB said:

Point of Order if I may M'Lud....

 

On a boat I think its called a "deck head", rather than a ceiling.

Only "Dick Heads" call it a ceiling