Changes to Part L

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Saw another post about the regs changing mid June (for applications) with then a year for work to start.

Given the cost of insulation at the moment, is it worth accelerating a BC application to get it in before the deadline to benefit from a cheaper build?

I’m thinking a PD 6 x 4m single storey extension here…

I appreciate that as an investment probably better insulation would save money in the long run, but this house isn’t my long term home.

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Saw another post about the regs changing mid June (for applications) with then a year for work to start.

Given the cost of insulation at the moment, is it worth accelerating a BC application to get it in before the deadline to benefit from a cheaper build?

I’m thinking a PD 6 x 4m single storey extension here…

I appreciate that as an investment probably better insulation would save money in the long run, but this house isn’t my long term home.

Views?
Deffo. Get your app in before June (15th?) or else be looking at 150mm cavitieso_O.

It's not just the insulation but the lintels, tie wires, window boards, cavity closers, etc. Ball ache.:rolleyes:
 
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It's getting out of hand.
The extra cost of the thicker wall insulation will take years to achieve payback; and the increase in thickness of walls will further reduce available space, especially when extending the back of a terrace house.
For a small 3m P.D. extension on the back of a narrow house, it will give very little extra space for a much higher cost, and it may not even be worth extending.
 
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Thanks guys, glad I’m thinking along the right lines :)

Re the cavities, I see you can keep a 100mm cavity if you use 90mm PIR and keep the 10mm cavity clear. However, given that it seems the PIR needs to be taped together, I just don’t see how it would be possible to manage it?! I used 50mm PIR and could only keep the cavity clear by working the course and then inserting the PIR after the outer courses were complete.

I’m sure better brickies than me would have less excess muck after laying…but I don’t see how you can clear any muck in a 10mm gap? Perhaps @noseall has some tricks??

Or perhaps a new tool needs to be invented for the job? :)
 
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Wow, thanks for this. I'm thinking of doing a front extension (got planning already).
If I get the building regs application in now and don't start until after June is that OK? Or perhaps get them around for a site visit...
 
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Thanks guys, glad I’m thinking along the right lines :)

Re the cavities, I see you can keep a 100mm cavity if you use 90mm PIR and keep the 10mm cavity clear. However, given that it seems the PIR needs to be taped together, I just don’t see how it would be possible to manage it?! I used 50mm PIR and could only keep the cavity clear by working the course and then inserting the PIR after the outer courses were complete.

I’m sure better brickies than me would have less excess muck after laying…but I don’t see how you can clear any muck in a 10mm gap? Perhaps @noseall has some tricks??

Or perhaps a new tool needs to be invented for the job? :)
Back in 2008 I did an extension and wanted to use 75mm Kingspan with a 25mm residual cavity (which I think was the minimum acceptable at the time). Building Control told me yhey wouldn’t accept less than a 50mm cavity due to risk of mortar bridging the gap, and told me I’d need to make my cavity 125mm overall. I decided to stick with rockwool.

Interesting that 10mm is now acceptable, but as you say, how is that residual cavity maintained? Some kind of 10mm board that can be raised up as work progresses?
 
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Thanks guys, glad I’m thinking along the right lines :)

Re the cavities, I see you can keep a 100mm cavity if you use 90mm PIR and keep the 10mm cavity clear. However, given that it seems the PIR needs to be taped together, I just don’t see how it would be possible to manage it?! I used 50mm PIR and could only keep the cavity clear by working the course and then inserting the PIR after the outer courses were complete.

I’m sure better brickies than me would have less excess muck after laying…but I don’t see how you can clear any muck in a 10mm gap? Perhaps @noseall has some tricks??

Or perhaps a new tool needs to be invented for the job? :)
We prefer the full fill (Dritherm) way of building. To build the blockwork first, to me is backwards. I will never willingly subscribe to that way of building.
 
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Wow, thanks for this. I'm thinking of doing a front extension (got planning already).
If I get the building regs application in now and don't start until after June is that OK? Or perhaps get them around for a site visit...
Based on the table in Ronny's link, you've got a year to start the work but you should definitely get your application in before 15th June

Screenshot 2022-05-19 at 07.40.49.png
 
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We prefer the full fill (Dritherm) way of building. To build the blockwork first, to me is backwards. I will never willingly subscribe to that way of building.
Ah I see, so 150mm cavities for you and the boys going forwards then?

I built my whole extension with the inner skin of two courses of thermalites first, then two courses of the outer skin, then 50mm PIR in, ties on top, then back to the inner skin for another too... but I'm just an amateur! :)
 
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I built my extension in timber frame and my walls were around 200mm in total. They would still out perform the new Part L requirements and are almost half the thickness of a new block / block wall with render and plaster and a 150mm cavity.

Not only would I have lost a lot of internal space, but also I wouldn't have fitted my kitchen in!
 
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Wow, thanks for this. I'm thinking of doing a front extension (got planning already).
If I get the building regs application in now and don't start until after June is that OK? Or perhaps get them around for a site visit...
If you get the Building Regs application in before 15th June, you then have up to 12 months to start work under the present insulation rules.
 

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