Cladding battens, Pressure treated or not

[gavztheouch]

Hi I have some 47x50mm pressure treated battens (The green coated ones) My screws to attach the battens are 180mm heco-topix that hold on 60mm insulation too. They have a standard galvanised finish. Im worried that they won't last the hopefully life of the cladding about 50 years. apparently the copper in the pressure treatment will cause the screw to rust fast. A solution would be to use stainless screws (very expensive @ 180mm) or change to a non copper based treatment. batten.

 

I have struggled to find decent battens at 50x50mm, most batten are made from crap wood. I guess I could have them milled from something naturally durable like larch but I assume there is a solution already out there or I am overthinking things again

[Duncan62]

I went with SS screws for what it's worth.

 

Same layup, 60mm external insulation, 25x50 counter batten. 50x50 batten. 

 

Once you start getting custom cut larch, the price must be similar?

[gavztheouch]

Thanks @Duncan62

 

Can I ask what brand/ type you went for.

[Kelvin]

Sihga stainless steel screws and Thermopine battens from Russwood. I also used the Kompefix ventilation strips as I got a good deal on them. I’ve visited two houses with vertical cladding and while the cladding was fine the underbuild battens had failed after 10 years. Mostly the screws but also some of the battens. 

[saveasteading]

6 hours ago, gavztheouch said:

battens at 50x50mm, most batten are made from crap wood.

Yes they usually have lots of knots, because they only span 600mm. the price relates to that.

ask your local timber merchant for better, quality. Tanalised is standard in 47 x 47 structural timber but it costs more. 

I think moisture is critical to corrosion, so internally should be no problem.  Given what it say here, there should be fixings with extra galvanising for exposed conditions.

 

 

[Duncan62]

On 04/08/2025 at 13:37, gavztheouch said:

Thanks @Duncan62

 

Can I ask what brand/ type you went for.

 

https://www.tcfixings.co.uk/product/a2-stainless-t25-part-thread-wood-screws-60mm-x-180mm/18642

[MikeSharp01]

On 04/08/2025 at 08:10, gavztheouch said:

A solution would be to use stainless screws (very expensive @ 180mm) or change to a non copper based treatment. batten.

We used Helifix inskew's stainless, they did the loading calcs and gave us a fixing schedule, dead easy to drive in with the SDS fitting good for pitched and vertical cladding - not expensive really. https://helifix.co.uk/products/warm-roof-fixings/inskew/

 

[gavztheouch]

Thanks everyone a few good options here. Looks like it’s a sensible option to use stainless steel.

 

just need to decide if I stick with the pressure treated spruce or ‘upgrade’ to thermopine. In theory the thermopine might be longer lasting but I guess it’s hard to prove without testing it myself for 50 years, which I can’t. My biggest worry was the screws rusting, I guess stainless helps there.

 

@Duncan62 did you have any issues with the stainless screws snapping. 
 

im hoping for 50 years out of the larch cladding which I think is possible. Some of our shed doors at the farm are wood and still in good condition. Need to decide if pressure treated spruce can match the 50 year lifespan 

[Duncan62]

8 hours ago, gavztheouch said:

 

@Duncan62 did you have any issues with the stainless screws snapping. 
 

 

Don't recall snapping any. stripped a hex head or two when I wasn't paying attention/pressure on the impact driver.

 

I and another guy installed all of ours, we're the careful types, not the bang it up types.

[Kelvin]

None of the Sihga screws broke. I have snapped other stainless steel and self cutting screws though. Slow and steady wins the day. 

[Nickfromwales]

5 minutes ago, Kelvin said:

None of the Sihga screws broke. I have snapped other stainless steel and self cutting screws though. Slow and steady wins the day. 

I almost got sucked into the vortex of looking at the many different screws I could buy and put into organisers, that may possibly get used, maybe,.......but I'd have them, lol.

[Kelvin]

55 minutes ago, Nickfromwales said:

I almost got sucked into the vortex of looking at the many different screws I could buy and put into organisers, that may possibly get used, maybe,.......but I'd have them, lol.

I could open a small hardware shop. The kind where you go in for a single screw, and some tape. I also have enough tek screws to build 10 garages. 

[Nickfromwales]

8 minutes ago, Kelvin said:

I could open a small hardware shop. The kind where you go in for a single screw, and some tape. I also have enough tek screws to build 10 garages. 

Get them listed on BH marketplace?

[Kelvin]

11 hours ago, Nickfromwales said:

Get them listed on BH marketplace?

I will do. I have a load of stuff to advertise but will do it all at once as I’ll need to dig it out from the workshop.