Fire Safety Regs - Timber Cladding

[Nickfromwales]

6 hours ago, Alan Ambrose said:

 

Would be interested to hear about that.

What would you like to know? 

[saveasteading]

6 hours ago, Alan Ambrose said:

But then they are selling the stuff. 😀

I've always found that they give the correct advice and don't  sell for the sake of it.

That's  good business too as they started with just the one passionate inventor: was it 25 years ago?

 

 

 

[Owain1602]

2 hours ago, john0wingnut said:

Interesting reading everyone’s replies.

BCO for me has stated it’s required and sent me a letter to that effect.

Hopefully the picture uploads. My issue is I have a tiny amount of room for batten / counter batten above the window, so I have no idea how I am going to run an intumescent strip along the top with  ventilation mesh all while leaving a gap to the soffit.

 

I’ll see if I can find this NHBC guide, but as it stands agree with others that none of the guides are clear cut

Not sure if there’s anything out of shot that we can’t see, but I’d say there’s no point putting intumescent strip above that window. Just use treated timber that’s 38mm or deeper to close it off, don’t think there’s anything worth ventilating there.

[Owain1602]

1 hour ago, Alan Ambrose said:

@Owain1602 >>> What are you going to do at the heads of the windows?

 

We used thin stainless strip as per an earlier ‘ub discussion. Quite a bit of work, but done now. Much cheaper than intumescent of course and seems to me anything fireproof will work (maybe not in the regs though) as you don’t need the expandability of intumescent.

Does that mean you aren’t ventilating the cavity above the window, nor allowing moisture that sits above the windows to make its way out?

[john0wingnut]

12 hours ago, Owain1602 said:

Not sure if there’s anything out of shot that we can’t see, but I’d say there’s no point putting intumescent strip above that window. Just use treated timber that’s 38mm or deeper to close it off, don’t think there’s anything worth ventilating there.

That’s a fair point.

I could just run intumescent strip along the very top by the insect mesh all the way around the extension.

[Great_scot_selfbuild]

Having thought I'd closed this topic off for our build, I find myself revisiting it as my builder (new to the project for this phase) who is looking at the timber cladding installation (diamond shingles) has raised a concern / query about the 9mm shingles and whether they are safe/compliant for our build. His background is large commercial / flats and so obviously this topic has consumed a lot of time and attention for him but from a very different perspective. Our build is a timber frame, Larsen truss walls with full-fill blown cellulose fill (continuous, no gaps/voids). The question which I'll be discussing with my PD when they're back is two fold:

 

1. Verify that this cladding (which I've seen used on other builds) meets BR and safety standards.

2. If our build is clad in a non-fireproof cladding, what is the point in fitting intumescent strips (where we still need airflow in normal use), if the cladding itself is likely to have burned away? (I haven't researched how quickly the strips expand vs. singles are likely to burn).

 

For further background, our BC has reviewed the drawings and seen the cladding, we are well over 1m from boundary and he raised no concerns.

 

Has anyone else found themselves having to 'show working' to prove compliance or assure others?

 

For clarity:

Single 2-storey, 4-bed private dwelling (well) over 1m from boundary, in England.

[Gus Potter]

14 minutes ago, Great_scot_selfbuild said:

Having thought I'd closed this topic off for our build, I find myself revisiting it as my builder (new to the project for this phase) who is looking at the timber cladding installation (diamond shingles) has raised a concern / query about the 9mm shingles and whether they are safe/compliant for our build. His background is large commercial / flats and so obviously this topic has consumed a lot of time and attention for him but from a very different perspective. Our build is a timber frame, Larsen truss walls with full-fill blown cellulose fill (continuous, no gaps/voids). The question which I'll be discussing with my PD when they're back is two fold:

 

1. Verify that this cladding (which I've seen used on other builds) meets BR and safety standards.

2. If our build is clad in a non-fireproof cladding, what is the point in fitting intumescent strips (where we still need airflow in normal use), if the cladding itself is likely to have burned away? (I haven't researched how quickly the strips expand vs. singles are likely to burn).

 

For further background, our BC has reviewed the drawings and seen the cladding, we are well over 1m from boundary and he raised no concerns.

 

Has anyone else found themselves having to 'show working' to prove compliance or assure others?

 

For clarity:

Single 2-storey, 4-bed private dwelling (well) over 1m from boundary, in England.

To get your head around this we need to understand what we are trying to do.

 

Objectives are in general terms:

 

1/ We want to prevent the spread of smoke and flames for long enough that folk can get out the house, or if disabled that the fire service can rescue them. Normally this is 30 minutes for a house like this. 

 

In no particular order.

 

The onus is on the home owner to not set light to neighbouring properties, based on fire of London act 1667.

 

The onus is also on the home owner to ensure that the structure of the house does not fall on the fire service and risk their lives. One great example here is below

 

https://www.firescotland.gov.uk/news/remembering-the-cheapside-street-fire-65-years-on/

 

But roughly here is what happened

 

The building's 60-foot-tall walls collapsed due to an explosion caused by the blaze that tore through the warehouse.

 

@Great_scot_selfbuild until you get a grasp of these basics you ain't going to make progress. 

 

What this means in your case is that you not just need to protect the occupants but also the structure. Now until you understand how the structure works, what bits can go on fire, what bits you need to protect and what are sacrificial then any advice BC or other wise give you could be a complete pile of mince, you need to ask where does the buck stop! It usually rests with someone like myself, not BC!  At the end of the day the law is likely to make you (me) responsible if you have an input into this design. 

 

Now I can see why you think, but the cladding could burn away, but if that is the case then you often need to detail the fire proofing for that case. Basically you need to stop fire and sparks getting up into the roof space or into window openings. 

 

34 minutes ago, Great_scot_selfbuild said:

2. If our build is clad in a non-fireproof cladding, what is the point in fitting intumescent strips (where we still need airflow in normal use), if the cladding itself is likely to have burned away? (I haven't researched how quickly the strips expand vs. singles are likely to burn).

You need to sit down and think this through. It's down to the detailing! Your builder is asking good thoughtful questions!