Boiled Linseed Oil - Preventing Rot

[cwhaley]

I have used lengths of untreated softwood timber (9" x 2") to make a small decked area and a step up to said area.

All timber is sat on concrete blocks (not soil or grass) and is raised around 10" off the ground.

Given that it rains a lot in this country, I have concerns over the wood rotting over time. I coated it all with a generous amount of boiled linseed oil before assembling but I'm just wondering if this will be enough?

Is this type of oil enough to give say 4 or 5 years' worth of protection?

 

[foxhole]

It will rot eventually , will be very slippery when wet if it’s smooth .

 

[cwhaley]

The boards for walking on are actually coated with a preservative and stain so no concerns over slipping -- it was the joists I was more concerned about.

 

[foxhole]

The boards for walking on are actually coated with a preservative and stain so no concerns over slipping -- it was the joists I was more concerned about.

Preservative and stain do not prevent slipping .

 

[bobasd]

i doubt that "Boiled Linseed Oil" will do much for rot prevention.
use the recommended chemicals - or pressure treated joists.

 

[JohnD]

Is this type of oil enough to give say 4 or 5 years' worth of protection?

No. Linseed oil is not fully damp-proof. You usually get spots and larger patches of black mould growing under the oil, if used outdoors.

I still use it for hardwood sills, but only after applying multiple coats of Cuprinol Wood preserver, and also a dark wood dye to hide the stains which remained even after rubbing down.

It smells quite nice when the sun gets on it.

It is easy to recoat every year or two.

You must not let oil lie on the surface, apply lightly with a brush or rag, after 10-20 minutes wipe off any that has not soaked in. Otherwise it will harden to a gummy varnish that is very difficultto remove.

The oily rags must be soaked in water and tied in a plastic bag as they can spontaneously combust (I have seen this happen in a painters cupboard) or you can use them to light the barbie. Spread out flat until needed, don't screw or roll them up or stuff into a container.

 

[cwhaley]

Preservative and stain do not prevent slipping .

No but there's a gazbo above the decking which stops most of the rain didn't mention it as it wasn't relevant to the question. The edges of the decking get wet and that's where I'm concerned about rot.

 

[cwhaley]

No. Linseed oil is not fully damp-proof. You usually get spots and larger patches of black mould growing under the oil, if used outdoors.

I still use it for hardwood sills, but only after applying multiple coats of Cuprinol Wood preserver, and also a dark wood dye to hide the stains which remained even after rubbing down.

It smells quite nice when the sun gets on it.

It is easy to recoat every year or two.

You must not let oil lie on the surface, apply lightly with a brush or rag, after 10-20 minutes wipe off any that has not soaked in. Otherwise it will harden to a gummy varnish that is very difficultto remove.

The oily rags must be soaked in water and tied in a plastic bag as they can spontaneously combust (I have seen this happen in a painters cupboard) or you can use them to light the barbie. Spread out flat until needed, don't screw or roll them up or stuff into a container.

Thanks, John. I compared the smells to a chip shop fryer actually! I coated the timber with a generous amount and did wipe away excess but after that just screwed the boards on top. Most of the timber stays dry due to the gazebo above it but the edges get wet from driving rain and that's where I'm concerned about rot. I think you have convinced me to use a wood preserver.

I've read lots on spontaneously-combusting oily rags but never heard of anyone experiencing it so thanks for the heads up. I tend to chuck anything like that onto the fire anyway as I get rags free from an upholsterer friend.

 

[JohnD]

When I opened the cupboard (I think on a Monday morning) because I could smell burning, it was full of white smoke. I rummaged about and found a biscuit tin of rags. I took it outside and tipped it on the ground, when I did, the rags in the middle were glowing red, and burst into flames with the fresh air.

The painters cupboard also contained dustsheets, paint, white spirit, brush cleaner, stripper... so could have easily set the building ablaze.