To seal or not to seal that is the question

[michael]

I have read with interest all of your praises for Ozmo oil as a finish for stripped floorboards which I believe you just apply directly onto the bear timber. However I have in front of me a tin of Liberon Floor sealer, an oil based finish/sealer which it claims:-

“Is ideal for achieving a satin finish on wood, stone and terracotta floors and can be used as a sealer prior to waxing with floor wax. Can also be used for sealing unvarnished cork surfaces and for enhancing the natural colour of new and old wood and stone.”

Could somebody please advise me if there are any benefits in sealing a wooden floor before applying a finish such as Ozmo oil for example.

I will be stripping a rather large area of floorboards later in the year and I want to make sure I do it correctly.

 

[Penners]

The benefits of sealing are twofold.

Firstly, if you have recently sanded the floor, the sealer will make the "nib"* stand up, and facilitate its removal by light sanding.

Secondly, the sealer will prevent the final finish from soaking variably into the wood and giving a patchy finish.

*Nib is the fine cut ends of the sanded wood fibres. When they've had a finish applied to them, they tend to stand up on end. Once the finish has dried, the nib then gives a rough feel to the wood, rather like the chin of a man who hasn't shaved for a couple of days.

The technique for "denibbing" is to allow the sealer coat to harden. Then sand lightly over the whole floor with a fine (preferably silicone carbide) paper. P220 grade is about right. Remove all dust before applying your finishing coat(s).

 

[Andrew Bodenham]

Having finished a couple of floors with Osmo products I can't imagine any benefit from applying another product before the Osmo finish. The Osmo product is designed for a two coat application onto bare wood, and works perfectly well as such.
Introducing another layer increases the work involved and there is a (slight) possibility of incompatibility between the different finishes. The coverage of the Osmo Polyx finish is outstanding.
Being oil-based the finish does not give rise to significant nibbing, but if this is a problem you can always sand lightly before the second coat. Meticulous removal of dust before starting is the key to a smooth finsh.
In my experience there is no problem with areas of different absorbency.
To summarise: follow the instructions on the tin and don't make things more complicated than they need to be.

 

[Penners]

I agree with Andrew. The post above answers the OP's question about the benefits of sealing, but if Osmo say apply two coats, then the first coat is probably acting as a sealer coat anyway.

 

[Toby Newell]

No.

If you must use osmo, use osmo. Sanding sealer will reduce the adhesion of any applied finish and is particularly not recommended in this case as it will stop the osmo penetrating the wood properly. Liberon is craft company, they don't sell to commercial trade in bulk. I can only imagine the product is a thinned out poly varnish with stearate/pumice type fillers (no sds sheet available on thier site) if I could change one mistake in my finishing piece in the finding out section, it would be when I say to use sanding sealer on floors, never! only pure dewaxed shellac and certainly not with an oil finish.

Toby