Necessary to seal a wooden gate after pressure washing?

[Rollerball]

Today I purchased a pressure washer to deal with the moss and algae growing on parts of my drive. Also decided to have a go at my wooden gate (not holding the washer too close to avoid any damage) and it's come up really nice, looks like new again. There was a fair amount of algae on it and it was almost black too due to its age. I think it may be pine, whatever the case it's a light wood.

Now that's done I'm wondering if I NEED to seal it. I mean is it now essential or just optional? Will I have stripped off a protective layer by pressure washing the gate? Presumably the wood was treated before I bought it and I've not applied any kind of sealant since then (it's nearly 20 years old). It's showing no signs at all of rotting anywhere.

BTW, the washer's max pressure is 120 bar (about 1700 PSI).


If I need to treat it then any recommendations on sealer make/type?

To add to this, I should have been a bit clearer regarding the wooden gate - it's a wide farmyard gate, 6 horizontal bars. As this has very likely been pressure treated does that mean it may not need to have a sealant of some type painted on since I pressure-washed it?

I'll look into whether or not it's been pressure treated, the manufacturer's metal label is still on it I think. But it's dark now and drizzling, I'll look tomorrow.

 

[JohnD]

you have just taken off the water-repellent coating

so unless it is a durable hardwood, it would benefit from another coating.

if you prefer, you can use a timber preservative that poisons fungi and insects. Pay extra attention to the parts near the ground, and surfaces that will be wet after rain.

If using both, use the preservative first, and allow to dry fully.

 

[Rollerball]

I see, thanks. Live and learn.

So I guess it's now a case of wait 24 to 48 hours for it to dry (once it stops raining) then seal.

I'd best not use anything that poisons fungi and insects as I have dogs who have been known to chew and lick all manner of things and, sod's law, they'd end up chewing or licking the gate after treatment.

How about something like the following for a two coat application?

https://www.amazon.co.uk/Raincheck-Universal-Breathable-Colourless-Waterseal/dp/B07QLSWKB4/

Or this:

https://www.amazon.co.uk/Roxil-Wood-Protection-Cream-Waterproofing/dp/B07PTR3H36/

(single coat)

must be pet safe of course when dry.

Edit: Boiled linseed oil is apparently pet safe:

https://www.amazon.co.uk/Palace-Langlow-Boiled-Linseed-1510900/dp/B07XJ6TLKR

 

[Rollerball]

To add to my post, I should have been a bit clearer regarding the wooden gate - it's a wide farmyard gate, 6 horizontal bars. As this has very likely been pressure treated does that mean it may not need to have a sealant of some type painted on since I pressure-washed it?

I'll look into whether or not it's been pressure treated, the manufacturer's metal label is still on it I think. But it's dark now and drizzling, I'll look tomorrow.

 

[JohnD]

I use linseed oil on hardwood sills, but it is not truly damp-proof and you often get black-stain or blue-stain under it.

Decking oil or stain is pretty good, and more durable than fence stain.

Fence stain is cheap and leaves a thin film, coloured and waxy, which repels water until the wax weathers away. You can check if it's still working by throwing a bucket of water at it. if it beads up and runs off, still working. It's cheaper than the decking treatments, and you can see it's not as good.

 

[Rollerball]

Thanks, that's really useful.

If the 'farm gate' is indeed pressure treated as I am currently suspecting does that indicate it may not need any kind of sealant, etc after pressure washing?

 

[JohnD]

I don't know.

preservatives might not go in very deep. They soak into end-grain better. Any cut-edges need re-treating. Dead knots need extra treatment because water can get into the interior.

The processes used for telegraph poles and railway sleepers are much more intense.

 

[Rollerball]

Thanks.