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Sealing around ducts


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Evening all,

 

MVHR has arrived & I've spent the day making a platform in the loft for it to sit on. Since its outside the vapour tight membrane the ducts will need to come down through it.  Has anyone got a cunning plan for this?  I wondered about getting some plywood, drilling appropriate sized holes for the ducts and then mounting the ply level with the joists - i should be able to get some silicone around the duct to help seal it.  Then tape the whole lot.  Overkill?

 

Any observations / advise welcome.

 

CC

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Thanks all for replies.

 

Plenums will have to go in loft - no way to run duct around in first floor joists really.

 

Support for plasterboard isnt the issue - being able to seal around the ducts that go down stairs through the first floor is the query really.

 

Been looking at grommets but with around 10 to do, I was trying to see if a cheaper option existed first.  I have a plan but I think it will be fiddly and time consuming. The real pain is where I've got several ducts all passing through through the vcl all in the same location - grommets will result in these being spread out.

 

Need to have a play I guess.

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I was impressed with EDPM tape, it was flexible and could be stretched and shaped. I'd make a board with holes in and start by sealing this down on the airtightness layer, next I'd put the ducts through and seal each one using the tape. As belt and braces I'd seal the gap between the board and each duct with low modulus silicone sealer first.

Edited by Triassic
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Morning Triassic,

 

Thats the idea I had in mind although now I've started looking at grommets they start to look tempting.  Any particular brand of EDPM tape you would suggest?

 

Cheers,

 

CC

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1 hour ago, CC45 said:

Morning Triassic,

 

Thats the idea I had in mind although now I've started looking at grommets they start to look tempting.  Any particular brand of EDPM tape you would suggest?

 

Cheers,

 

CC

 

What sort of terminals are you looking at ..? If they are the BPC ones, is it the right angle ceiling ports as I would have thought they'd be pretty easy to just seal to a piece of ply and then align and put a couple of screws straight through the plasterboard into the ply ..?

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  • 2 months later...

Have a look at the Tyvek range of tapes. Flexwrap NF may suit you. I used some to seal around the solar thermal pipes coming through the roof. It is pleated so makes it easy to form around odd shapes like pipes ducts etc.

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Hello,

 

Been investigating further.....

 

Does anyone have any comments / observations of the following:

 

Tesco varna profil 12/48

Contega solido 12/68

 

Gerband 12/48 and 12/88.

 

Tempted to use the Gerband.

 

Thanks in advance for any replies.

 

C

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I have been using the Tescon Vanna tape, the standard one on a 60mm wide roll.  I need to buy some more so I too am interested in cheapest place to buy this stuff and similar alternatives.  The only alternative I have experience of is the Sega tapes but they are even more expensive than the Tescon.
 

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1 hour ago, CC45 said:

Hello,

 

Been investigating further.....

 

Does anyone have any comments / observations of the following:

 

Tesco varna profil 12/48

Contega solido 12/68

 

Gerband 12/48 and 12/88.

 

Tempted to use the Gerband.

 

Thanks in advance for any replies.

 

C

I used gerband membrane and various tapes and was impressed. They where a 1/3 of the price of the pro clima tapes when I bought a few years ago.

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All these airtight tapes are expensive. The cheapest I found was getting them in Germany. Got the Pro Climate Tescon Vanna and the profil 12/48. You'll need Google Translate turned on for some of it. Free shipping if you buy a few rolls.

 

http://www.baunativ.de/

 

I did look at other cheaper and some unbranded stuff but was worried if they failed or lost the stickiness after 5 or 10 years I'd never get access to repair or replace them.

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5 minutes ago, Dudda said:

All these airtight tapes are expensive. The cheapest I found was getting them in Germany. Got the Pro Climate Tescon Vanna and the profil 12/48. You'll need Google Translate turned on for some of it. Free shipping if you buy a few rolls.


 

http://www.baunativ.de/


 

I did look at other cheaper and some unbranded stuff but was worried if they failed or lost the stickiness after 5 or 10 years I'd never get access to repair or replace them.

That looks like good prices. How much do you have to spend to get free shipping to the UK?

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14 minutes ago, ProDave said:

That looks like good prices. How much do you have to spend to get free shipping to the UK?

100 euro to Ireland which is only 5 rolls and you'd need at least that for a small house. You can get the airtight mastic and intello membranes from them too and are cheaper so spending enough for free delivery isn't hard. I presume it's similar price range for the UK if not cheaper as it's closer. Delivery took 4 days. I've used them twice.

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39 minutes ago, Dudda said:

100 euro to Ireland which is only 5 rolls and you'd need at least that for a small house. You can get the airtight mastic and intello membranes from them too and are cheaper so spending enough for free delivery isn't hard. I presume it's similar price range for the UK if not cheaper as it's closer. Delivery took 4 days. I've used them twice.

The best I have seen for the Tescon Venna was about £20 a roll from someone on ebay from Ireland, but the postage to the UK was expensive. so 5 rolls free of postage at that price sounds good.

 

I am almost certainly going to buy the Protect Barriair membrane which is very similar to the non reinforced Intello, which Jewsons have quoted me £99 per roll which is still cheaper than that site.

 


 

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16 hours ago, CC45 said:

Bought Sica sicrall off ebay - box of 10.  Less than £200 delivered from Germany.  Impressed with the tape. Got 1 roll left so need more now.  Angling towards Gerband at the minute.

 

 

There's been a bit of Siga Sicrall stuck to the side of one of my long levels for around 3 years now.  It's been left out in the rain, bright sunshine, covered in concrete and washed off and I've tried to pick it off a few times.  It's still there, and short of taking a chisel to it I don't see it coming off in my lifetime...............

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It is very good, tempted to order another box of 10 and then sell surplus.

 

Going to order some Gerband split release tape for the windows and doors.  Thats the next two weeks (evenings and weekends) sorted!

 

C

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On ‎07‎/‎02‎/‎2017 at 23:14, CC45 said:

Hi @DRT,

 

Will start on this shortly - where did you get hold of it?

 

Cheers

Sorry not been back to you lost my broadband connection last week only just got it back. I had a Sample pack of tapes and brochures from Tyvek there was enough of the tape to just seal around the solar HW pipes. I have used a lot of the acrylic tape and double sided tapes from their range and I got  them from Huws Gray builders merchants but don't think they have the flexwrap. I found Tyvex to be very helpful with  information etc so they could tell you who stocks it.

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