Tongue and groove

[Admiral.snelson]

So I am about to clad the ceiling of our 60ft NB with tongue and groove. Does anyone have advice on this?

 

I am looking at 14mm spruce, but have noticed that you can get finished MDF 9mm for much cheaper, is MDF ok to use? if not should i paint the reverse of the spruce with aluminium primer or is that a bit over the top? Is 14mm over the top, would 9mm spruce be ok?

 

Any advice is greatly received.

 

Thanks

[RobinJ]

So I am about to clad the ceiling of our 60ft NB with tongue and groove. Does anyone have advice on this?

 

I am looking at 14mm spruce, but have noticed that you can get finished MDF 9mm for much cheaper, is MDF ok to use? if not should i paint the reverse of the spruce with aluminium primer or is that a bit over the top? Is 14mm over the top, would 9mm spruce be ok?

There are arguments for sealing/not sealing!

 

I would on priciple avoid MDF and prefer solid wood, allowing it to breath.

Depending on whether you are using rockwool, sprayed foam or kingspan type insulation, will depend on how much water gets trapped between ceiling and top, but this will soon dry out.

This and leaks can lead to stains appearing, but I think it is easier to remove them from solid wood than MDF or veneered surfaces!

 

One suggestion is to install and then allow a few weeks for drying out, sand down and varnish or paint. This may stop cracks showing, but if the wood is properly seasoned and allowed to stand on the boat before fitting, it should be minimal anyway.

[Paul C]

Make sure you put every wire, fitting, etc behind it before you fit it. Our boat has T&G roof and sides (above gunwhale) and I've never been able to remove it, its been fitted that well! Had to route some new cables in a different direction avoiding it, because I just coulnd't get it off again without damaging it. It was secured using a nail gun or something into battens, maybe there is a way of neatly fitting it without making it difficult to remove in the future though.

[Admiral.snelson]

We have a coating of spray foam (thin layer applied by previous owner) with 25mm kingspan on top to build it up. Time is our main factor at the moment so we are leaning towards mdf with a wood trim, I have seen finished MDF which will obviously be sealed on both sides. A friend of mine has said that I should go for as thick as possible, but i'm not sure of the reason for this on the ceiling.

[BargeeSpud]

I'd say it can't hurt to seal the underside of whatever material you're putting up against the insulation. A bit belt & braces, but you'll KNOW it won't be absorbing any moisture that might arise. I'd also say that real wood can take a little moisture better than MDF which swells & doesn't fully go back on drying out, in my experience.

Edited March 15, 2013 by Spuds

[fudd]

I've used beaded moisture resistant mdf on our boat. Can't see any problems. It's 10mm thick. We've been on a summer and two winters. No probs at all. Zero. Bone dry front and back. There's a lot o prejudice involving it. Solid wood is lovely but it moves a lot. So does sheet material but if you know what you are doing and fix it correctly it won't be a problem. Only if it sinks and then that's the least of your problems. Our boat is well vented though.

Steve P.

[Chalky]

Paint the back of the timber with preservative. Use invisible nailing clips. Arrange the planks so they all start and stop at the same batten. only secure 1 end to the batten, leave the other clipped so it can move. Put a finisher over the plank end to end joins and secure with clear silicon. Wax the whole lot, don't varnish. This will allow the whole lot to expand and contact with heat and moisture and will stop it cracking and splitting. This is the way I put the roof up the second time - the first was varnished etc and split. I ended up taking it down and re-doing it. Using the approach described it's been ok for 9 years.

[ditchcrawler]

I've used beaded moisture resistant mdf on our boat. Can't see any problems. It's 10mm thick. We've been on a summer and two winters. No probs at all. Zero. Bone dry front and back. There's a lot o prejudice involving it. Solid wood is lovely but it moves a lot. So does sheet material but if you know what you are doing and fix it correctly it won't be a problem. Only if it sinks and then that's the least of your problems. Our boat is well vented though.

Steve P.

I used MDF over 12 years age, the boat has been in use for 12 years. We are not live aboard, so it gets hot, cold and damp. I have even filled holes where I have moved down lights, Its machined T&G and painted white. So far it has given no problem at all. I had a leak where the hatch is fitted over the engine room, the water was literally running in and I would suggest it has done much better that wood would have done.

[Admiral.snelson]

I'm leaning towards using this, what do you think

http://www.wickes.co.uk/finished-mdf-cladding-9x144x2400mm-pk4/invt/162849/

[fudd]

I'm leaning towards using this, what do you think

http://www.wickes.co.uk/finished-mdf-cladding-9x144x2400mm-pk4/invt/162849/

 

The stuff I use comes in 8x4 sheets bit of wastage but not enough to worry about. It will never split and is easy to fit.

[ditchcrawler]

I'm leaning towards using this, what do you think

http://www.wickes.co.uk/finished-mdf-cladding-9x144x2400mm-pk4/invt/162849/

I would go for a damp resistant or waterproof one, also a lot less work fitting full size sheets than strips.

[RobinJ]

There's a lot o prejudice involving it.

I think most of it is due to the toxicity involved in cutting and trimming, once fitted and sealed it should no longer be a problem!

[Bee]

Probably best to treat both sides the same whatever you use to avoid it `cupping`, Painted t& g looks nice, so if you can handle large panels and you want to paint it mdf is perfectly ok.

[Ally]

Personally I wouldn't use MDF on a boat. Some say they have good experience with it, but I've seen it in a bad state on many boats, some in less than a year. You may be fine, but if yours does deteriorate as many do, would you want the hassle & expense of replacing it, for a small saving now?

Use timber. We use hard wood t&g, and double oil it front & back before it goes up. (unless the customers want it painted, when we then use tulip wood, primed, undercoated, & glossed before fitting, then glossed again after,) we use 11mm thickness, & stagger the board ends so it runs through, no cross trim needed.

Finally, you will pay your money & take your choice, but for me, I wouldn't want to risk having to replace.

And yes, I wouldn't want to work with mdf regularly, if at all. Its a banned product in some countries, for health reasons.

Edited March 15, 2013 by Ally

[Tuscan]

Personally I wouldn't use MDF on a boat. Some say they have good experience with it, but I've seen it in a bad state on many boats, some in less than a year. You may be fine, but if yours does deteriorate as many do, would you want the hassle & expense of replacing it, for a small saving now?

Use timber. We use hard wood t&g, and double oil it front & back before it goes up. (unless the customers want it painted, when we then use tulip wood, primed, undercoated, & glossed before fitting, then glossed again after,) we use 11mm thickness, & stagger the board ends so it runs through, no cross trim needed.

Finally, you will pay your money & take your choice, but for me, I wouldn't want to risk having to replace.

And yes, I wouldn't want to work with mdf regularly, if at all. Its a banned product in some countries, for health reasons.

 

 

If your budget stretches I agree go for hardwood, you only want to do his once.

[Keeping Up]

When our boat was built, the builders (Stoke on Trent) told us they always fit the T&G with the tongue just slightly withdrawn back from its limit in the groove so that there is room for expansion and movement. In fact tthey make their own T&G with a longer tongue and deeper a groove so they can allow for even more movement. It certainly seems to work well, as it is still good after 21 years.

 

ETA the whole lot was treated in woodstain, front and back, before fitting so it's never needed varnishing.

Edited March 15, 2013 by Keeping Up

[ditchcrawler]

If your budget stretches I agree go for hardwood, you only want to do his once.

There is MDF and there is MDF, I had a piece of the stuff I used on the boat in water for a year, I have seen other just blow to pices as soon as it gets damp. That is why I suggested he didn't buy the imitation boards from Wicks.

[smileypete]

I'm leaning towards using this, what do you think

http://www.wickes.co.uk/finished-mdf-cladding-9x144x2400mm-pk4/invt/162849/

Reading the description it looks like a non-moisture resistant grade and would have to be sealed very well and pinned in place very well or it might sag.

 

Their 14mm timber T&G isn't much more in price, one thing to bear in mind with painting is to seal the knots with a shellac sealer or knotting solution. Or better still, *after* the boards are properly acclimatised use an all over coat of shellac based primer like Zinsser BIN.

 

BIN costs a bit and pongs while drying but goes a long way, it's a better vapour barrier than most coatings too so will minimise movement after fitting. If cutting the boards after coating give the ends a quick coat of BIN while you put them up.

 

cheers, Pete

~smpt~

Edited March 16, 2013 by smileypete

[Ally]

I second zinsser if you're painting it.

[fudd]

There is MDF and there is MDF, I had a piece of the stuff I used on the boat in water for a year, I have seen other just blow to pices as soon as it gets damp. That is why I suggested he didn't buy the imitation boards from Wicks.

I suggest not buying anything from wickes. The t&g sheets they sell are only 6mm thick and will be of poor quality. My stuff is twice the weight of Wickes mdf. When its machined it doesn't fluff up. It's available in 8x4 4x8 10x4 and also 20mm thick. Good stuff but not traditional.

As far as I am concerned, the quality of Wickes products is below standard. When I rewired my house I bought boxes of MK sockets. MK is a top brand but in every box there was, one that would have a screw missing or one that was cross threaded. Crap. Ones I bought from an electrical retailer were fine. Yer spends yer money ............

[ditchcrawler]

I suggest not buying anything from wickes. The t&g sheets they sell are only 6mm thick and will be of poor quality. My stuff is twice the weight of Wickes mdf. When its machined it doesn't fluff up. It's available in 8x4 4x8 10x4 and also 20mm thick. Good stuff but not traditional.

As far as I am concerned, the quality of Wickes products is below standard. When I rewired my house I bought boxes of MK sockets. MK is a top brand but in every box there was, one that would have a screw missing or one that was cross threaded. Crap. Ones I bought from an electrical retailer were fine. Yer spends yer money ............

Agree

[DHutch]

Proberbly less of an issue with MDF, but if you are T&G'ing it as Allen said, you want to space it out a little (maybe 1mm, using a steel strip as a spacer as you nail it on) to allow for expansion, bearing in mind slightly where its been before you put it up, ideally in the boat acclimatising.

 

I would personally prefer solid wood, but in sure MDF is ok too, worse case while not ideal, in 10 years time you can do it differently!

 

I would also 'back' it with a coating of some form or other, even if just a slosh of undercoat or a single coat of varnish if going for a clear finish on the a-side. This will make the taken of moister more even, reducing cupping as one side gets takes it on before the other.

 

 

Daniel

[Ally]

Also leave a slight gap end to end, as boats grow & shrink lengthwise too. I saw one cabin tightly butted up that had buckled lengthways over winter. Doesn't need much gap, & it depends also on the temperature when fitting.