Airtight wall chases

893bet

I am currently pricing a number of electrical contractors for wiring of my new build. None of them have any experience of making wall chases airtight on external wall though all interested in learning.

My understanding is a plaster of bonding of sort is used to "parge" the chase around the socket and up the wall chase a few feet also.

Can some link to the exact product they recommend? A premixed product would be my preference.

Also when is this done? Are these done one at a time when socket boxes and conduit are being put in? or can they all be done at once before that is done. (my brain says they are done as the socket boxes are put in so to get a snug airtight seal).

893bet

Anyone?

gman2k

You will probably get a better response over in the Construction and Planning forum
http://www.boards.ie/vbulletin/forumdisplay.php?f=876

893bet

gman2k wrote: »

You will probably get a better response over in the Construction and Planning forum
http://www.boards.ie/vbulletin/forumdisplay.php?f=876

I was thinking that in first place but said I'd try here first!

Can a mod move please?

The Hill Billy

Moved as requested.

tHB

rampantbunny

Looking into this myself at moment. A friend used a proprietary product to plaster his internal walls, not the usual sand and cement. Not sure if he used it for wall chases but I'm considering it because it is advertised as a good performer in airtight tests.

Others have used light coat of sand/cement in the chases. I've also considered using a thick silicon type paint-on substance which is used as a waterproofing/water stop product. Very hard to apply though so still considering other options.

Can't specifically name products here so...if GYPsies did plastering, they'd sell something that was airtight. They mITE not be able to spell all that well so airtight mITE be slightly different. Failing all that PM me for more info.

BTW - the product I'm alluding to is not premixed.

hexosan

I thought about a liquid sealer, had been looking into it for my floor and if it makes concrete water proof I can't see how it wouldn't make block work airtight.

rampantbunny

hexosan wrote: »

I thought about a liquid sealer, had been looking into it for my floor and if it makes concrete water proof I can't see how it wouldn't make block work airtight.

Can you PM name of product if you have one in mind. Will look it up.
If it is a sort of paint it could possibly be sprayed into the chase and would be a very fast job.

The water stop product I mentioned would be perfect but don't know if there is a spray gun capable of applying it. Would rather trowel on plaster than paint with that stuff.

hexosan

rampantbunny wrote: »

Can you PM name of product if you have one in mind. Will look it up.
If it is a sort of paint it could possibly be sprayed into the chase and would be a very fast job.

The water stop product I mentioned would be perfect but don't know if there is a spray gun capable of applying it. Would rather trowel on plaster than paint with that stuff.

Is that the black tar like stuff in the bags you showed me before.

rampantbunny

It is indeed (except grey)...'quare stuff' as one lad put it. But I doubt there's a paint brush developed yet to cope with it, or if there is then your arm wouldn't last long trying to spread it.

BarneyMc

Looking for advice here also. I believe the 'pink skim' stuff works well for this job?

rampantbunny

BarneyMc wrote: »

Looking for advice here also. I believe the 'pink skim' stuff works well for this job?

That's what fclauson used...but think it was the standard bonding stuff (AFAIK there are multiple different products within the companies range for different applications).
Same crowd do a specific 'airtite' version I mentioned above.

I think we'll soon be overthinking this. Sand & cement, 'pink stuff', paint on 'tar'...they'll all do the job I'm sure. I'm just going to try and pick the one that's easiest to apply and doesn't cost a fortune.

BarneyMc

rampantbunny wrote: »

That's what fclauson used...but think it was the standard bonding stuff (AFAIK there are multiple different products within the companies range for different applications).
Same crowd do a specific 'airtite' version I mentioned above.

I think we'll soon be overthinking this. Sand & cement, 'pink stuff', paint on 'tar'...they'll all do the job I'm sure. I'm just going to try and pick the one that's easiest to apply and doesn't cost a fortune.

Yes I'm not sure how any of these can be applied into a narrow track in the wall? The box part might be a bit easier but still doesn't allow much space either.

Airtight tape would be easy and for all that's used not that expensive?

rampantbunny

BarneyMc wrote: »

Yes I'm not sure how any of these can be applied into a narrow track in the wall? The box part might be a bit easier but still doesn't allow much space either.

Airtight tape would be easy and for all that's used not that expensive?

I have a tape that has a fleece coat on it (not a thick fleece or anything, more a fibrous surface) that can take plaster. It is to be used around window reveals from marine ply to internal block work. I'm not sure I believe that it will never crack so if I do use it around windows I'll be putting expanded metal over just in case.
Personally I don't want the hassle of doing the same thing for every affected chase. Could be the perfect solution but what price for peace of mind.

893bet

Knowledge is sparse on the ground where I am.

Builders merchants look at me like i have two heads
Electricians the same (but interested to learn)
Architect about as useful as $%%£ flavoured lollypop

Airtight tape in the chase wont work as the chase is too narrow from what I can see and I just cant see it getting the chase airtight. I have called my airtight supplier (partell) and they recommended pink bonding or tile grout to seel roughly a metre up from socket box/switch. Fill the chase with the bonding/plaster and push the conduit and box into it and scrap of the excess that comes back out then if required. They also recommended a product to seal around the junstion between the conduit and the socket box.

BarneyMc

893bet wrote: »

Knowledge is sparse on the ground where I am.

Builders merchants look at me like i have two heads
Electricians the same (but interested to learn)
Architect about as useful as $%%£ flavoured lollypop

Don't get me started... the lack of knowledge in this industry is disgraceful.

893bet wrote: »

Airtight tape in the chase wont work as the chase is too narrow from what I can see and I just cant see it getting the chase airtight. I have called my airtight supplier (partell) and they recommended pink bonding or tile grout to seel roughly a metre up from socket box/switch. Fill the chase with the bonding/plaster and push the conduit and box into it and scrap of the excess that comes back out then if required. They also recommended a product to seal around the junstion between the conduit and the socket box.

So you need to push the box and conduit in while the pink bonding is setting or can it be done when it has hardened?

hexosan

BarneyMc wrote: »

Don't get me started... the lack of knowledge in this industry is disgraceful

++++++++++++1 to that

hexosan

BarneyMc wrote: »

So you need to push the box and conduit in while the pink bonding is setting or can it be done when it has hardened?

My understanding is you need to push it in while its setting.

rampantbunny

hexosan wrote: »

My understanding is you need to push it in while its setting.

I 'plan' on filling the chases while the electrician is there but he'll be the one pushing the boxes into the chase. Last thing I want is to be responsible for getting all the boxes laser level and having see-sawing/out of alignment wall plates. The plan will work assuming he turns up when he is supposed to.

Aren't the back-boxes to be screwed to the wall also? If they are, the ultimate effort would be to drill the holes first and insert the wall plugs. Then apply the pink stuff, push in the box and fix with the screws (which will be perfectly aligned through the existing holes in the box itself!!). A better seal than drill through afterwards.

Easy as that..what could go wrong.

ht9zni1gs28crp

Had a chat with my Electrician last night, he has seen a few attempts but mainly the plugging of the cable ducting to stop air travelling down. But correct me if im wrong but isn't most of the air coming in through the Block work itself?

Ideally id like to think a bonding agent into the chases would work easiest, then drill and fix the socket into it?

Would be nice to see some actual real world tests!

rampantbunny

My electrician had same idea of sealing conduit, but admitted that this was only effective if your conduit began it's journey from lets say the attic space which might be outside the airtight envelope.

I suppose if you seal the conduit and chase at the top, seal where it enters the back box, and seal the box itself, even if air gets into the chase, where can it go.
It' s hardly going to come out through the skim coat that covers the conduit.

The mind boggles with this airtight stuff...
Michael Jackson used a hermetically sealed tent (I read somewhere)...look what happened him.

@miller_63, apparently you only need to seal the wall chases that are on external walls, and on internal walls which are 1m or less from external walls. Plus around the door frames too.
Who came up with the 1m figure ..not a clue.

hexosan

My electrician has suggested using a waterproof concrete sealer painted into the chases he's convinced that if it seals concrete to water penetration well then air can't pass through it either.
I wish I was as confident as him. In theory it makes sense, if only I could find some one who's tried it.

BarneyMc

hexosan wrote: »

My electrician has suggested using a waterproof concrete sealer painted into the chases he's convinced that if it seals concrete to water penetration well then air can't pass through it either.
I wish I was as confident as him. In theory it makes sense, if only I could find some one who's tried it.

Can you reveal the sealer details so we can check out its properties, durability, etc.? I'm not sure I'd take the chance. Why not just use the 'pink stuff'?

hexosan

BarneyMc wrote: »

1. Can you reveal the sealer details so we can check out its properties, durability, etc.? I'm not sure I'd take the chance.

2. Why not just use the 'pink stuff'?

1. He just suggested didn't name any particular product. (That part was left for me to discover)

2. Laziness.

ht9zni1gs28crp

Its a bizarre situation allright, I have asked two of the leading Passive house experts in Ireland for their opinion or recommendation on products...not a peep out of them in response.

So its really a whole trial and error jobby!

893bet

miller_63 wrote: »

Had a chat with my Electrician last night, he has seen a few attempts but mainly the plugging of the cable ducting to stop air travelling down. But correct me if im wrong but isn't most of the air coming in through the Block work itself?

Ideally id like to think a bonding agent into the chases would work easiest, then drill and fix the socket into it?

Would be nice to see some actual real world tests!

I spoke to an expert in Airtightness ( the guy runs the Airtightness courses for metac and also owns a company that sells Airtightness tapes, membranes).

His detail was pink plaster or tile grout in the chase and also to seal the conduit/socket junction.

BarneyMc

893bet wrote: »

... and also to seal the conduit/socket junction.

... with the pink plaster/tile grout?

893bet

BarneyMc wrote: »

... with the pink plaster/tile grout?

No they have a generic type product for this that is used in various situations around the house. It is a mastic sealant that comes in a silicone type tube.

rampantbunny

893bet wrote: »

No they have a generic type product for this that is used in various situations around the house. It is a mastic sealant that comes in a silicone type tube.

How much would a tube of this mastic cost? What is the coverage like?
I've an aversion to buying stuff that only comes in tubes, because it's usually tarted up silicon to begin with.
Skeptical I know, but I have bought items from some airtightness experts at a premium and it turns out it can be bought online in a variety of guises for far less.

893bet

rampantbunny wrote: »

How much would a tube of this mastic cost? What is the coverage like?
I've an aversion to buying stuff that only comes in tubes, because it's usually tarted up silicon to begin with.
Skeptical I know, but I have bought items from some airtightness experts at a premium and it turns out it can be bought online in a variety of guises for far less.

No idea of coverage. They are same size as a tube of silicon anyway as I have 10 or so tube bought already for another job.

Roughly around 11quid per including VAT I think.

Flood

893bet wrote: »

I have called my airtight supplier (partell) and they recommended pink bonding or tile grout to seel roughly a metre up from socket box/switch. Fill the chase with the bonding/plaster and push the conduit and box into it and scrap of the excess that comes back out then if required. They also recommended a product to seal around the junstion between the conduit and the socket box.

In theory this plan sounds good but filling the chase and attempting to push the conduit into the chase deep enough so you wont have any problems with plaster cracking after will be difficult, time consuming and a very messy process.
The chase unless you chase extra deep will not work with having bonding etc shoving it out.
Why dont you cut the chases 3/8 inch wider and have room either side of the conduit to fill in whatever material you want. Remember to seal off the top of the conduits too.

893bet

Flood wrote: »

In theory this plan sounds good but filling the chase and attempting to push the conduit into the chase deep enough so you wont have any problems with plaster cracking after will be difficult, time consuming and a very messy process.
The chase unless you chase extra deep will not work with having bonding etc shoving it out.
Why dont you cut the chases 3/8 inch wider and have room either side of the conduit to fill in whatever material you want. Remember to seal off the top of the conduits too.

I am having trouble visualising also and can see the above problems arising myself.

I guess it's a matter for having your electritions on board and willing to give it the attention it needs.

Flood

Maybe wiring from below up would be an easier approach, less filling in etc. This presents its own obstacles but I have several houses wired in the past this way and a planned approach works just fine.
One can achieve away better test figures as cable runs are shortened significantly.

BarneyMc

Flood wrote: »

Maybe wiring from below up would be an easier approach, less filling in etc. This presents its own obstacles but I have several houses wired in the past this way and a planned approach works just fine.
One can achieve away better test figures as cable runs are shortened significantly.

Where do the cables sit in the floor (at what level)?

Flood

BarneyMc wrote: »

Where do the cables sit in the floor (at what level)?

What type of floor are you on about?

BarneyMc

Flood wrote: »

What type of floor are you on about?

Sorry, maybe I misunderstood. If the wire is coming from below then it must be coming from the floor?

Flood

BarneyMc wrote: »

Sorry, maybe I misunderstood. If the wire is coming from below then it must be coming from the floor?

I may have understood you, yes of course it will. Wont it be less of a problem from below?

BarneyMc

Flood wrote: »

I may have understood you, yes of course it will. Wont it be less of a problem from below?

Maybe. Anyway just curious as to where the wire sits, below, between or above the insulation layer?

Flood

BarneyMc wrote: »

Maybe. Anyway just curious as to where the wire sits, below, between or above the insulation layer?

What are you classing as the insulation layer?

BarneyMc

Flood wrote: »

What are you classing as the insulation layer?

The layer of insulation. Nite :rolleyes:

Flood

BarneyMc wrote: »

The layer of insulation. Nite :rolleyes:

How am i expected to go between a layer. Nite :rolleyes:

rampantbunny

Flood wrote: »

How am i expected to go between a layer. Nite :rolleyes:

I understand what Barney is asking. I don't know the dictionary definition of a layer but I'd hazard a guess that there is a top and a bottom to it...therefore you can go above it or below it (the cable that is, not you).

Take your suggestion to run cables up the wall rather than down and think of your ground floor.
The floor might be made up of a concrete slab layer, DPM layer, insulation layer, screed layer, finished floor layer. Where in all these layers do you run the electrical cables in order to meet the wall, and then chase upwards.

Flood

rampantbunny wrote: »

Where in all these layers do you run the electrical cables in order to meet the wall, and then chase upwards.

Same place the plumber runs his pipes, thought that would be very obvious.

BarneyMc

Flood wrote: »

How am i expected to go between a layer. Nite :rolleyes:

If it's the insulation layer then lay down 1 slab of insulation, e.g. 70mm, cut a groove (if required) to take the wires, lay the wires in the groove, then place the next slab of insulation, e.g. 70mm on top. the wires are now in the insulation layer.

If it's the finished floor then lay the wires on top of the insulation and apply the sand/cement or liquid screed. The wires are now in the finished floor layer.

I'm just asking if either of these are viable because I'm not in the trade and don't know.

Getting back to your advice to take the wires from bottom up, where should the wires lie in the floor? Let's drop the 'layers' word and thanks (genuinely) for any advice.

rampantbunny

Flood wrote: »

Same place the plumber runs his pipes, thought that would be very obvious.

Wouldn't be obvious to us hence the question...we're mostly self building. Putting the cables in beside or underneath water pipes I'd have thought to be a no in case of potential burst pipes/water leaks. The devil is in the detail and you only get one chance at something like this.

hexosan

On the ground floor I dont see this as an option unless you have a basement below.
On the first floor it'd work and run them on the ceiling of the ground floor. Only problem would be chasing through the Airtightness wrap of the slab and then having to core/drill the slabs at each chase.

ht9zni1gs28crp

Has anyone actually tried to tape airtight membrane into the sockets?

I had a lot of success at the weekend with a trial method of this, so much so I kept going and got all the sockets done. Takes up far less space than any grouting or bonding will do too...

hexosan

miller_63 wrote: »

Has anyone actually tried to tape airtight membrane into the sockets?

I had a lot of success at the weekend with a trial method of this, so much so I kept going and got all the sockets done. Takes up far less space than any grouting or bonding will do too...

Any pics or description of what you done.

How many chases and how much tape used

ht9zni1gs28crp

hexosan wrote: »

Any pics or description of what you done.

How many chases and how much tape used

I will get some pics up later once I have transferred them over to the PC.

Using Intello membrane offcuts and the Tescon Vana tape I was able to recess the membrane into the socket chase and tape the edges to the outside, I suppose a lot like papering a cake tin. The Tescon Vana sticks well enough to the block and plastering over shouldn't be a problem

Perfecting the cut to the square socket of Membrane was the trick, leaving enough/a sliver of membrane to go up the wire chase.

In reality I had 11 sockets/switch chases to do, not a lot I guess compared to others (I have minimalised as much as possible external wall sockets/switches) the cost of the extra tape is minimal I guess compared to the hassle of bonding/plastering within the chase.

Timewise, once perfected its quick and easy.

BarneyMc

miller_63 wrote: »

I will get some pics up later once I have transferred them over to the PC.

Using Intello membrane offcuts and the Tescon Vana tape I was able to recess the membrane into the socket chase and tape the edges to the outside, I suppose a lot like papering a cake tin. The Tescon Vana sticks well enough to the block and plastering over shouldn't be a problem

Perfecting the cut to the square socket of Membrane was the trick, leaving enough/a sliver of membrane to go up the wire chase.

In reality I had 11 sockets/switch chases to do, not a lot I guess compared to others (I have minimalised as much as possible external wall sockets/switches) the cost of the extra tape is minimal I guess compared to the hassle of bonding/plastering within the chase.

Timewise, once perfected its quick and easy.

I guess this has the added advantage of not having to be there at the same time as the electrician.

ht9zni1gs28crp

Sorry for delay in uploading pic. Here is a sample double socket.

Where the conduit enters the plug the electrician will plug the gap in the conduit between the wire and also any gap between the conduit and the plug box. If this makes sense. What do you lot reckon?