Wood Preservative / Treatment for rafter ends etc

[Krome10]

Hi folks

We're doing some work on the house that will expose the rafter ends, and various other woody bits around the top perimeter of the house. Some is already exposed, and whilst not looking pristine, I think it's sound enough. There's signs of woodworm, but all looks to be historic. Nevertheless, whilst it's exposed and accessible I thought it wouldn't hurt to slap on some treatment, even if it is more for prevention rather than cure.

I've found this:

https://www.toolstation.com/triple-action-wood-treatment/p34502
And I've also been reading a little about Boric Acid based preservatives.

Any thoughts on these two options and/or recommendations for others?

Is it even worth doing the rafters if only the ends can be reached?

Many thanks

 

[Phil Pascoe]

Rot will creep in through the ends, so yes. I used 5* Cuprinol on mine - I had six inch fascias on eight inch timbers, so the bottom inches were exposed. I treated all the ends when I replaced the fascias.

 

[Krome10]

Thanks Phil.

I'll take a look at the 5* Cuprinol. The Everbuild stuff I linked too says that external timer must be overcoated with a varnish or similar. That would be a pain. I'll see if the Curpinol says the same. That being said, would the end of the rafters and the wall plate be classed as external seeing as they are behind fascias/soffits? Guess they're kind of on the cusp of being internal/external!

The Everbuild also says to "Avoid contact with bitumen, roofing felt or plastics" That's not going to be possible because the timbers are quite hard to access, so on the most part it will be a case of stuff a long brush into the gap and hoping for the best. So the felt and plastics are likely to at least get some treatment on them....

 

[pe2dave]

Any wood exposed to varying moisture / temp will move? 'overcoated with varnish' seems to be a recipe for disaster? Surely a better solution would be something to soak into the end grain?
Cheapest Wickes treatment lasted 8 years on a compost bin, possibly worst conditions for wood?
I'd seek something similar, but pay a bit more for wood supporting your roof?

 

[Jones]

Ronseal decking end grain preserver is good for cut ends in treated timbers. Many of the newer wood preserver treatments are water based so won't affect old felt, a plant sprayer can be used which will be easier and more effective than a brush. Borate is effective against wood borers it comes as a powder you mix with water and then spray apply. Even with a long wand on the sprayer it's hard work to get everywhere and it will only work on the surfaces that have been covered.
Varnish overcoat is needed on exposed timber to stop rain leaching out the preservative, if it's dry in a roof there's no need.

 

[Seascaper]

Is it even worth doing the rafters if only the ends can be reached?

If you have a garden pump up sprayer you will find this useful for reaching into the gap and spraying the rafters. Use a combined woodworm and preservative treatment. You will be able to see if woodworm is live by seeing clean new flight holes and new wood dust under the holes,
Regards

 

[Phil Pascoe]

If you have a garden pump up sprayer you will find this useful for reaching into the gap and spraying the rafters. Use a combined woodworm and preservative treatment. You will be able to see if woodworm is live by seeing clean new flight holes and new wood dust under the holes,
Regards

and wear a mask.

 

[Phil Pascoe]

Thanks Phil.

I'll take a look at the 5* Cuprinol. The Everbuild stuff I linked too says that external timer must be overcoated with a varnish or similar. That would be a pain. I'll see if the Curpinol says the same. That being said, would the end of the rafters and the wall plate be classed as external seeing as they are behind fascias/soffits? Guess they're kind of on the cusp of being internal/external!

The Everbuild also says to "Avoid contact with bitumen, roofing felt or plastics" That's not going to be possible because the timbers are quite hard to access, so on the most part it will be a case of stuff a long brush into the gap and hoping for the best. So the felt and plastics are likely to at least get some treatment on them....

I used C 5* as it was the only one I used at the time. It's expensive, but for most purposes not much is used. Any reputable preservative should be fine. You'll be surprised how much the end grain will soak up though. I wouldn't class it as external - it's covered over and doesn't take any weathering.

 

[Krome10]

Hi

Thanks for all the responses. To answer some of the points raised...

- Overcoating with varnish or similar. That's just for exterior wood and it seems the reason is more environmental; to stop the product leaching out and causing harm (as @Jones says). Seeing as the rafters etc won't be subjected to weather, I think that won't be needed.
- I'm pretty sure the Everbuild is water-based, yet it still says you must keep it off flt, insulation, etc.
- Spraying - the trouble with that is that you must avoid getting it onto the felt, insulation, and plastics. Spraying indiscriminately is likely to get it onto all of the above!

The gap really is quite tight, so not sure how much of the rafters I'll reach. Likewise the wall plate - I'll be able to do the front face and possibly the top, but that's it.

Photos are really hard to take because the gap is small, but I've taken some to show what's what and also the condition of the wood which is better than I expected, and all pretty much solid to the touch. At the end of the day, I always cringe when I read "Very toxic to aquatic life with long lasting effect" and the like, so if I need not use anything then I'm happy to leave it!

Cheers

 

[Krome10]

Actually, having thought about it some more I might have a plan...

Since taking those photos, all of the gaps have been temporarily stuffed with plastic sacks and the like to prevent anything getting in the loft and setting up camp there. Rather than remove the "stuffing" before applying treatment - which I initially planned to do - I could just push it deeper in so that it acts as a shield to prevent the treatment getting where it shouldn't.

On top that, this will allow me to use my leaf blower to remove all the crap from the timbers before treating them (including loose fill vermiculite insulation). I had scrapped the idea of using it because I was worried about how much it would blow up into the loft itself...

Cheers

 

[rafezetter]

Hi folks

We're doing some work on the house that will expose the rafter ends, and various other woody bits around the top perimeter of the house. Some is already exposed, and whilst not looking pristine, I think it's sound enough. There's signs of woodworm, but all looks to be historic. Nevertheless, whilst it's exposed and accessible I thought it wouldn't hurt to slap on some treatment, even if it is more for prevention rather than cure.

I've found this:

https://www.toolstation.com/triple-action-wood-treatment/p34502
And I've also been reading a little about Boric Acid based preservatives.

Any thoughts on these two options and/or recommendations for others?

Is it even worth doing the rafters if only the ends can be reached?

Many thanks

I've recently just used this myself for treating a new fence and seems to be good stuff, not cheap granted, but soaks in really well and dries as though it isn't even there, so no sheen or anything - not that that matters on rafter ends.

looks like you've definitely got either old or existing woodworm, no way to tell really, so treatment is definitely required depite it feeling solid.

 

[Krome10]

Hi all

I've been away but I'm back now and finishing off the wall prep, which includes treating these timbers.
I spoke to Cuprinol today and they said it doesn't matter if I get their product on plastics, the roof felt, etc. Also spoke to Everbuild who confirmed that plastics, roof felt, etc. must be covered to protect them from their product. I went on to ask what would happen if it did end up on plastics, etc. and they said it could soften them.

I presumed they would be made up of more or less the same ingredients, but perhaps that's not the case then? Anyone know whether they have the same ingredients or not?

Interestingly though, I did see that the Cuprinol says: "Ensure timber is fully dry (allow 3 days) before laying plastic floor tiles, foam or rubber-backed carpets, loft insulation, etc."

Cheers

EDIT:

They're hard to decipher, but looking at the SDS of both products, the hazardous components look very similar. Mind you, those SDS's are hard to decipher! And I guess is could be a non-hazardous ingredient that causes the problem with plastics.

For reference:

https://res.cloudinary.com/diq3xoeg...Everbuild_Triple_Action_Wood_Treatment_V6.pdf
https://www.cuprinol.co.uk/datashee...b_en_five_star_complete_wood_treatment_bp.pdf

 

[okeydokey]

Look at Sadolin products Ive found very good particularly the wood stain which Ive used on rafter ends and mock Tudor boards has lasted/kept the colour for say 20 years and going strong.

 

[Krome10]

Thank you very much - I'll take a look.