Laying solid flooring in a boat - to glue or not to glue...

[Doodlebug]

Hi all,

 

Boats getting there (slowly!) And i'm ready to lay the flooring. Problem is I'm trying to 'future proof' the boat at the same time.

 

The instructions for the flooring say I should glue it down. Or I have a nailing tool for nailing the floor to the joists. Both of these options I would add a trap door to - so the bilge can be accessed.

 

The third option is not to glue or nail and just hope the tongue and groove hold together.

 

What should I do. Will I ever need to access the entire bilge or is a trap door enough.

 

Is glue better than nails - I assume nails squeak? Or is there a better way...

 

Hope that makes sense, i'm falling asleep whilst typing. Still got lessons to plan for tomorrow - the joy of being a teacher!

 

Thanks!

 

Doodlebug

[Neil Smith]

I would screw down then its easy to get up again if needed.

 

Neil

[Taslim]

^^

 

As Neil said.

 

Use brass or stainless steel screws as part of the 'future proof' bit 'cause they're easyer to remove when the time comes.

[Phil Ambrose]

As Taslim said but just use stainless screws.

Phil

Edited September 15, 2015 by Phil Ambrose

[John V]

I'm PARANOID about access and I have discrete panels that are screwed down (minimum screws) sitting on very thin neoprene at the joints.

 

(mark you this is possibly from living on a 90 year old boat)

 

 

edit to explain....the panels are built up on ply sheets

Edited September 15, 2015 by John V

[Bee]

If I was buying or just looking at a boat for a friend I would really, really, want to get a look under the floor.

[Mike Jordan]

If you are using solid wood flooring as your post seems to imply you must make allowance for the timber to expand with increased atmospheric moisture. The length of the boards remains the same for all practical purposes but the width will increase with the take up of moisture. The natural inclination is to butt the boards tight up to one another and avoid gaps. If you do this and screw the boards down you will not stop the expansion! The pressure involved is enormous, it can move bulkheads and furnishings and cause all manner of problems.

If screwing the boards down it's recommended that you temporarily insert coins or washers to ensure a gap of about 2mm between each board, in addition a gap of at least 12mm must be left at the sides of the floor (normally covered by the skirting board)

Suppliers of solid wood flooring tend to sell an adhesive which sets like soft rubber and allows you to get away with butting the boards and allowing the adhesive to move under pressure. The adhesive is expensive but it works, it should be ideal for use where the maximum width of flooring is about 2 metres and a gap is left at the sides.

The engineered flooring based on 4mm of hardwood bonded to a plywood base material is much more stable but costs more than the solid material.

I have seen instructions attached to packs of flooring which advises you to leave the materials in the area where they are to be used for a period of 48 hours to "condition" this is supposed to solve the problem. Its nonsense but it probably sells flooring.

Best of luck with the project.

Mike.

Edited September 15, 2015 by Mike Jordan

[Mike Jordan]

Just had another look at the OP and note that you are fastening direct to the joists, all the flooring normally sold is intended for use on top of existing flooring.

All the above remarks are still true but if you are using the solid hardwood flooring sold in packs of random lengths you will not be able to match the length to the joist centres. that would mean that the shorter boards are, as you say, just hanging on the tongues. Please don't even think about it.

[magnetman]

Put an 18mm ply floor down first

 

I have put down about 15 square metres of teak finger parquet (several thousand individual fingers ) onto my plywood floor. Fingers are about 5 inch by 1 inch x 3/8 thick (125x25x9mm) all reclaimed from houses having new flooring. Most of it has been down about 18 months.

 

Anyway I used Lecol 5500 adhesive and no expansion problems at all and not a single loose finger. Its latex based adhesive AFAIK.

 

wide planks will no doubt be more of a problem.

 

If I need to access the bilge in the cabin (fairly unlikely with a 15mm base plate) I will drill and jigsaw out a section of floor as and when required there is a stern bilge inspection hatch where any condensation will gather anyway.

 

I think for planks fixed down to joists I would go with stainless screws.

 

 

Edit to add where the surface is 9ft wide I have let in a 10mm polypropylene rope down the centre to accomodate expansion just in case but it doesn't seem to move at all summer or winter.

Edited September 15, 2015 by magnetman

[magnetman]

[John V]

That's a lovely job Magnetman !!!

 

That rope expansion joint is clever !!! (and I reckon that looks great as well)

[starman]

We have 18mm solid oak t&g flooring laid on ply sub floor. The advice from the supplier (who also supplies a couple of boat builders) was to secret screw each plank through the tongues using special Spax screws which can be driven with no pre-drilling as little as an inch from the ends of the tongues without any splitting.

The screws (I forget the name but a GOOD merchant will advise) were brilliant. The floor went down easily and has been fine for three years now.

[Chewbacka]

I used a bamboo floor laid floating onto 19mm WBP ply base.

I chose bamboo because it is ok for conservatories and bathrooms.

 

It does move about a bit, not that you can see, but enough that a couple of holes drilled for door bolts (bad idea) sometimes line up and sometimes they don't. I glued the planks to each other along the tongue using pva as per the instructions. I left an expansion joint half way down the boat as the width is fine but I was worried about the length. 3 years on and it still looks good.

 

The down side of bamboo is it is much softer than oak so the surface is not as tough, but so far not a problem.

As said earlier, if I ever want to get below I shall use a jig saw. I hope this never happens..........