[C320-list] Cabin sole subflooring

[Dave Hupe]

Jeff-
Great recommendations.  That was a nasty old floor ..... Very nice transformation.
Dave Hupe1994 C320 #32

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  On Thu, Sep 10, 2020 at 12:08 PM, Jeff Hare<Catalina at thehares.com> wrote:   Hi David,

This is a little long, but feel free to contact me directly if you want to chat..

Located relatively near you is Forest Plywood (https://forestplywood.com/product/marine-plywood/).

You'll certainly want to be using Hydrotek BS1088 (or if you're ok with a little more money, Joubert Okoume) both are made to BS-1088 standards.

This plywood has marine glue, many more layers than subfloor and zero voids. It's built more like cabinet plywood. This is especially important, because this guarantees that no matter where you cut into a sheet of it, you'll never expose an interior void.  That would be bad.

One thing to note about 'marine' plywood. It rots just and delaminate like any plywood if not sealed properly, just that the glue is less affected by moisture. Hydrotek also handles steam/heat which can delaminate other woods.  Think of a water heater hose going off and dumping 5 gallons or more of steaming hot water in the bilge. 

If you are going to use Lonseal (which I've used successfully in the past), Defender has decent pricing on it. Buy the special notched trowel they recommend there as well. Grooves are slightly different than one for tile and that matters.  Don't buy the Lonseal adhesive they sell for it. It's a tricky mix ratio and will be super challenging to use in small batches. You have to mix the whole amount at once.  Instead, You can now use colloidal silica Thickened West Systems epoxy to mayo consistency. I have the tech application notes in PDF from the Lonseal tech guys on how to mix West Epoxy for this if you want it.

You'll want a gallon of denatured alcohol and a bunch of clean rags.  1) it cleans up the unthickened epoxy from tools and elsewhere.  2) you'll want to mix up batches of thinned (~10%) west epoxy to paint/seal the underside and edges of the plywood prior.  Only the underside and edges since the Lonseal epoxied to the top will seal that surface. If you try to seal the top surfaces, the epoxy will leave some unevenness that will telegraph through the surface of the lonseal over time.

Final suggestion is that you use your old flooring parts (if the bottom sides are in good shape and smooth) to lay over the top of the lonseal when laminating it so that you can put LOTS of weight distributed over the piece while it cures.  Sheetrock buckets with sand work pretty well.  Smooth flat garage or basement floors help ensure that your laminated panels end up flat.

Draw reference marks in sharpie on the edges of the plywood where you need the laminate stripes to end up so that they line up really well from panel to panel.  I also cut the lonseal about an inch or so oversized on all edges to give myself room to adjust/shift the orientation. It also helps keep epoxy from getting on the top finish surface, but the alcohol on a cloth can wipe that off before curing.

Also, finally, I used a laminate roller to press out the surface and remove any possibility of air bubbles prior to adding the sand buckets on top (separated by the old flooring or pieces of luan plywood cut to the same shape).

At the very end, I cut the Laminate back to pretty close to the plywood and then used a belt sander to trim it up perfectly.  You can see pics of a project I did with it here:  You can see 

https://c320.org/mediagallery/album.php?aid=296

Note that a that the C320.org site needs a software upgrade and may fail to render if you try to log in.  Clearing your browser cookies may allow it to display.  Hopefully I can fix that soon.  You may also be able to see it here but you have to be logged in on facebook for that.

https://www.facebook.com/media/set/?set=a.10154139644939066


-Jeff Hare
Woodbine II

-----Original Message-----
From: C320-list <c320-list-bounces at lists.catalina320.com> On Behalf Of David Veeneman
Sent: Thursday, September 10, 2020 9:07 AM
To: C320 Assn Forum <c320-list at lists.catalina320.com>
Subject: [C320-list] Cabin sole subflooring

I’m getting ready to replace my cabin sole with Lonseal marine flooring on a 3/4” plywood subflooring. Here’s my question: Do I need to use marine-grade plywood for the subflooring, or will standard subflooring plywood from Home Depot do? I’m going to seal the plywood with an epoxy-based sealer.

Thanks for your help!

—
David Veeneman
SV Adelante #131
Dana Point, CA