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VCL general questions ans some specifics


BMcN

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I am looking into how I will be applying the VCL once the kit it up.  I have a few questions if anyone can offer some help.

 

 From the floor up (solid slab), my plan was to join the VCL to the DPM for the slab. 

 

On the top of the ground floor kit, I had planned to run a length of VCL right around, then place the joists on top, bringing the VCL around and back under the second storey kit - this sound correct?

 

The VCL will then be run across the upstairs ceilings to create the envelope. 

 

I will be using Protect Barriair VCL with integrated tape.  Is this sufficient?  I have seen butyl tape recommended however it is very expensive.

 

Lastly, for now, To the rear of the house we have an integrated garage with attic trusses.  The room above will be part of the living space upstairs.  What is the best way to include this in the airtight envelope?  If the VCL is to insulation side, this would mean either putting it down before the 22mm caberfloor, in which case is would get damaged.  Or placing on top of the caberfloor, again where is would be damaged.  I have attached screenshots of floor plans to show this area.

 

Thanks in advance.

Screenshot 2019-06-30 at 21.23.54.png

Screenshot 2019-06-30 at 21.24.12.png

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I'll chip in.

 

Your plan to wrap around the joists is standard - it tends to get referred to as a 'Tony Tray'.  Running it under the joists upstairs is fine.  You can batten out from there to give a service void - saves puncturing the vcl which would occur by running cables through the loft.  

 

The garage - rather than put the VCL above/under the caberdeck flooring, take it round the joists again so it runs below the floor joists.  You will have to plastervoard the ceiling in the garage to meet fire regs for the room above.  That will cover/protect your VCL 

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38 minutes ago, LA3222 said:

I'll chip in.

 

Your plan to wrap around the joists is standard - it tends to get referred to as a 'Tony Tray'.  Running it under the joists upstairs is fine.  You can batten out from there to give a service void - saves puncturing the vcl which would occur by running cables through the loft.  

 

The garage - rather than put the VCL above/under the caberdeck flooring, take it round the joists again so it runs below the floor joists.  You will have to plastervoard the ceiling in the garage to meet fire regs for the room above.  That will cover/protect your VCL 

Thanks @LA3222.  Yeah that rings a bell from when I was researching previously.

 

By placing the VCL on the underside of the garage joists, wouldn't this place it on the cold side?

 

 

Screenshot 2019-07-02 at 22.54.04.png

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  • 3 weeks later...
On 07/07/2019 at 08:22, BMcN said:
On 07/07/2019 at 08:22, BMcN said:

Anyone else able to offer any advice?

 

Thanks

 

Anyone able to offer any advice for above the garage? 

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Don't trust the inbuilt tape in the Protect Barriair.  I found some was starting to come unstuck before I plasterboarded.

 

I "solved" this by screwing strips of plasterboard offcuts over all the joints (those that did not coincide with studs and hence service void battens) to keep the taped joint held tight in a sandwich.

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Treat it like two separate envelopes. The issue will be how you deal with the areas with the purple arrows. For attic truss I cut small squares of pir insulation then foamed them in place  However when you have services going in and out of the joists then it's very tricky so I used pir and cut out holes where electric cables or plumbing pipes where then taped round them onto the insulation to get it sealed up. It's not an easy job because of where it is. I had the ceiling below boarded out and first fix all done so I could use the ceiling and flooring to help form the squares with the joists.

IMG_20190728_183031.jpg

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1 hour ago, ProDave said:

Don't trust the inbuilt tape in the Protect Barriair.  I found some was starting to come unstuck before I plasterboarded.

 

I "solved" this by screwing strips of plasterboard offcuts over all the joints (those that did not coincide with studs and hence service void battens) to keep the taped joint held tight in a sandwich.

 

 

What tape would you recommend?  I see the tescon recommended and was intending on using it around windows etc, but it is quite expensive to do every joint.  Something like this?

 

https://www.permagard.co.uk/radbar-single-sided-foil-vcl-tape

 

@Declan52  I can VCL as shown on your green which will make the ceiling, eaves and uprights airtight.   My concern is the floor/ceiling of the garage, as the VCL needs to be on top of the insulation in the bottom chord.  What about using painting the 22mm caberfloor with airtight paint and then taping the VCL onto this?

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19 minutes ago, BMcN said:

 

 

What tape would you recommend?  I see the tescon recommended and was intending on using it around windows etc, but it is quite expensive to do every joint.  Something like this?

 

https://www.permagard.co.uk/radbar-single-sided-foil-vcl-tape

 

@Declan52  I can VCL as shown on your green which will make the ceiling, eaves and uprights airtight.   My concern is the floor/ceiling of the garage, as the VCL needs to be on top of the insulation in the bottom chord.  What about using painting the 22mm caberfloor with airtight paint and then taping the VCL onto this?

If you use d4 glue on the floor it expands and will give you your airtight seal on the joints. Depending on what you're walls are going to be you need to seal the gap you leave between the floor and the wall. You can use tape for this.

For the ceiling you could do something as simple as double boarding it and tape and seal the first layer to the walls. It will also help as a sound and fire barrier.

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I didn't want to rely on the floor being air tight, in particular how would you seal the VCL to the underside of the boards?

 

So I laid conventional DPM over the joists with the joints taped and taped to the wall VCL then laid the flooring.

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