Shed floor bodge job

diyadvice123

Hi Folks,

Recently bought a steel shed which came with an untreated plywood floor (Not marine grade).

Shed will be used for bikes coming in and out during winter and so wanted to treat the plywood against water damage. I went to small local DIY and got suggested fleetwood decking oil.

I've put on one coat but am now concerned this was a stupid move as the decking oil still stinks after 5 days and am worried about risk of breathing in smell/anti mould stuff when inside the shed (although this wont be for long periods as its just for storage). While the steel shed has some ventilation at eaves and airflow beneath suspended floor it doesn't have a window to leave open.

What would you do in this scenario?

Leave as is - it'll be grand when its fully cured and you're overthinking it.

Strip the decking oil and/or paint over it with a more suitable finish (Messy).

start from scratch and replace the plywood

Lumen

You could probably apply an oil-based varnish over the top of the decking oil. Then it'll smell of varnish instead. 😂

I would leave for at least a month before making any decisions.

Doop

Leave the door open as much as possible ie over night etc and it will subside.

jack of all

If it's an oil finish unless it has driers in it may never dry fully so not sure how a further varnish coat will improve matters. As Lumen suggests leave it be for a few weeks there's still great drying at the moment and reassess the oil finish then. Polyurethane floor paint is not overly expensive and would give a good finish on ply if 2 coats were applied, polyuethane floor varnish would do the same job, though both will need good drying conditions to cure.

Lumen

https://www.boards.ie/discussion/comment/119507986#Comment_119507986

As I understand it, oils are intended to polymerise over time into.... essentially hard plastic.

It's not so much drying as chemical transformation, although there may be additives in the product that do evaporate over the first few hours/days.

Doing any internet research on this is really hard, as oils marketed in the US tend to be closer in composition to varnishes, and most English language content on the interwebs is from the US.

Lumen

One other thing, the parts of plywood that generally need most protection from water are the cut edges, because if water gets in there the plywood will delaminate. Marine ply isn't generally more water resistant on the surface, it just has fewer voids in the glue (and higher quality glue, I think). It'll still swell and delaminate if unprotected, it just doesn't fall apart quite as much.

Aside from the glue, you can get different grades of ply, the really expensive stuff is hardwood throughout, then hardwood faced is cheaper, then softwood throughout.

Anyway, applying protection only to the top will "only" help with small spills and wet muck walked in, and maybe that's enough if the shed is well built and dry.

I've used a few different finishes on ply, and the easiest/best was water based poly varnish, but you can't use that over an oil finish.

The Continental Op

Door open AND A FAN might speed things up. I really wouldn't worry about the smell, you aren't going to be sleeping in there ;-)

diyadvice123

thanks all for the valuable advice. Have been keeping the doors open and smell is subsiding.

@Lumen i think your description of polymerizing is accurate. from the closest technical sheet i found online the finish is ".. is a solvent-borne alkyd resin combined with oil and other water proofing additives ". from what i read the alkyd resins cure to a plastic type finish (though some dont). Confusing stuff alright to research and completely agree about US based products/marketing outweighing what we see on shelves here. Bit of a guessing game for those of us without deep chemistry knowledge!

I think ill take on the advice here and leave it be for the month and reassess then if needs be.

Thanks again all