Should I treat my shed with something, bearing in mind it is made of pressure treated wood? (I mean some sort of preserving product, not a meal out!)

It was put in in October, so pretty new.

Should i expect pressure treated wood to be waterproof? in really heavy rain where the sides of the shed get wet, there are a few damp patches on the inside of the walls.

If it’s worth treating it, what would make it waterproof?

Thanks!

not a meal out!

🙂

But seriously, it can’t do any harm, can it…

Edit : I treat mine once every couple of years with some of that cheap Wilko shed treatment stuff. I thinks it’s water based so it’s not all that. Rain beads up similar to DWR on jackets but it seems to soak in under extreme weather or at the base of posts and lower stuff.

There has to be something better out there…

I was a little disappointed to find damp patches, I assumed the pressure treated wood would be waterproof. Perhaps it’s just rot proof not waterproof?

Any other suggestions for a really good waterproof treatment?

Perhaps it’s just rot proof not waterproof?

This.
Definitely not waterproof.
No harm in adding Cuprinol Shed and Fence (it’s good stuff), but I don’t personally like the stain colours.

Only needs treating for cosmetic purposes. That’s the beauty of pressure treating. My fence I put up 20 years ago was pressure treated and is still going strong. She’d companies usually guarantee pressure treatment for 10 years for rot, but it will last a lot longer than that.

10 years for rot, but it will last a lot longer than that.

I seem to remember a Grand Designs where there was some sort of community buildyerown project and they’d used pressure treated softwood for a veranda. In the revisit episode it had rotted through in the 10 year period between programmes. There was some continual exposure to a water source IIRC, so I guess that’s not your average use.

As widge says, pressure treatment is protection against rot and infestation, it is not a waterproofer (my guess with regard to the deck mentioned above is that the treatment was compromised by cutting and/or fixings).

Pressure treated wood will fade to grey in time so further applications of treatment will maintain some colour; a treatment that offers a uv protection is useful.

The cladding on sheds will either be tongued & grooved or lapped; rain can drive through gaps between boards and through knot holes. If you want 100% waterproof, you’ll probably need to line the shed with a dpm (damp proof membrane) of some sort. HTH 8)