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POSIs : treated or not?


ToughButterCup

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the recommendation in the relevant British Standard is that all structural timber should be treated even when it's internal and theoretically safe from rot. The reason for the recommendation is due to the risk factor if something goes wrong. The last thing you need is dry rot starting in your floor timbers due to....say, a slow leak from a pipe or radiator.

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24 minutes ago, PeterW said:

Never seen one made with treated ..! So if it’s an option I’m not sure unless they ones I’ve had have been done with something clear ..

it's highly likely that its a clear treatment

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5 minutes ago, Ian said:

the recommendation in the relevant British Standard is that all structural timber should be treated even when it's internal and theoretically safe from rot. [...]

 

There is no question that's too basic to ask on BH is there? Thanks @Ian  (Good screen name that, good name).

The price difference is £3 per POSI.

No brainer, then. 

 

 

 

Untreated. ?

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4 hours ago, recoveringacademic said:

Minera have just quoted for our POSIs.

I'm wondering why there is an option for untreated metal web joists. Why would anyone want their floor structure to be more likely to rot?

 

I have got soooo much to learn.

Good Question Ian

somtimes trusses and joists are required to be treated for woodworm 

But quite rare

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  • 10 months later...

Im making the same decision, treated or untreated.

 

Like @PeterW, I don't think Ive ever (knowingly) seen treated web joists. My quote is asking an additional 12.5% for treated.

Im considering it because my progress is slower than a snail on sedatives and the joists will be exposed until the autumn.

 

@Ian BS5268 Part 5 covers the Code of practice for the preservative treatment of structural timber. I can't read it for free online, do you know if it says structural timber must be treated if exposed for a certain period or is it purely a recommendation?

 

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I'm in exactly the same position and found some suppliers will treat the timber but I haven't looked into it with too much detail. One thing you may want to confirm is what "treating" means to them, as some suppliers mean for woodworm etc and not rain/moisture. 

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1 hour ago, willbish said:

Im making the same decision, treated or untreated.

 

Like @PeterW, I don't think Ive ever (knowingly) seen treated web joists. My quote is asking an additional 12.5% for treated.

Im considering it because my progress is slower than a snail on sedatives and the joists will be exposed until the autumn.

 

@Ian BS5268 Part 5 covers the Code of practice for the preservative treatment of structural timber. I can't read it for free online, do you know if it says structural timber must be treated if exposed for a certain period or is it purely a recommendation?

 

Once the joists go in will you not put your flooring down though which will offer a bit of protection. A few sheets of dpm and some sand will help to cover it up and keep the floor protected if your not going for one of the waterproof type boards.

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1 hour ago, Declan52 said:

Once the joists go in will you not put your flooring down though which will offer a bit of protection. A few sheets of dpm and some sand will help to cover it up and keep the floor protected if your not going for one of the waterproof type boards.

Im not going for a weather proof board.

My plan is to chuck down temporary OSB, I can get 20 sheets painted one side for £100 and wait until the roof is on before installing the permanent chipboard.

 

If I cover the whole area in DPM the water still has to drain off somewhere. I can't see the joists staying dry.

 

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18 minutes ago, willbish said:

Im not going for a weather proof board.

 

IMHO that’s a mistake. Glue and bond Egger protect to the joists as they are fitted and it will make the floor structure much stronger and safer for working. Looking at that layout, £100 would pay for the extra on the Egger and it’s a job done once. 

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37 minutes ago, PeterW said:

 

IMHO that’s a mistake. Glue and bond Egger protect to the joists as they are fitted and it will make the floor structure much stronger and safer for working. Looking at that layout, £100 would pay for the extra on the Egger and it’s a job done once. 

 

Now you're making me think again @PeterW

 

Egger protect is guaranteed for 60days exposed. If I install at the same time as the joists I will far exceed this.

That's why I thought a temporary deck first then a permanent deck when in the dry.

 

I had thought the permanent deck I would use wouldn't need to be a water proof one but I think what you are saying is water proof board is good to have regardless of whether it is exposed or not? Because of potential damage from bathrooms & leaks etc

 

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Anything other than P5 is a false economy anyway - you never know where you may get a leak and you’ll save £150..?? 

 

You need the Egger D4 glue and plenty of pairs of gloves as it goes everywhere as it foams up. Anyone working below should really wear a hat and clothes they don’t like ..!!! Ask @AnonymousBosch about getting it out of clothes...

 

We did a deck with it in early April, and put the final roof on in August and it had some pretty grim amounts of rain - pools of water and a quick brush off and it’s down the stairwell..! You glue the joints and it makes it pretty watertight - I had one seam that seems a little raised in a bedroom but a quick whizz over with a DA and the edge has gone. 

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6 hours ago, willbish said:

Im making the same decision, treated or untreated.

 

Like @PeterW, I don't think Ive ever (knowingly) seen treated web joists. My quote is asking an additional 12.5% for treated.

Im considering it because my progress is slower than a snail on sedatives and the joists will be exposed until the autumn.

 

@Ian BS5268 Part 5 covers the Code of practice for the preservative treatment of structural timber. I can't read it for free online, do you know if it says structural timber must be treated if exposed for a certain period or is it purely a recommendation?

 

The British Standard is purely a recommendation. It is not compulsory however all commercial work is specified to be compliant with British Standards

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6 hours ago, willbish said:

Egger protect is guaranteed for 60days exposed. If I install at the same time as the joists I will far exceed this.

That's why I thought a temporary deck first then a permanent deck when in the dry.

 

Exactly the same problem I will have :(

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+1 on egger board glued, my builder used it and through the winter there was standing water on it for weeks whilst the upper walls were built and roof put on. I was nervous about this but after plastering the protective covering was removed and not a single damp water mark ?. He also used no nails or screws (just on the first boards to stop them moving) and we have a solid no squeak floor.

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Its likely I'll have the roof on in a small number of months but I'm not going to risk it. 

So far with this build I've avoided ongoing rental costs such as scaffolding, heras fencing, portaloo etc. Even abandoned plans for a highway licence for the scaffold, £70/month, no chance.

As a result I've reduced the time pressure on myself and I think increased my enjoyment of the build so far.

The egger board is going in the same category; not worth the stress of having to meet a deadline.

 

 

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My egger protect was exposed throughout winter, easily 4 months, had snow sitting on it and countless soakings.  I’ve had to belt sand the joints as they swelled despite what I thought was liberal use of d4.  Otherwise they’ve survived.

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