Airtight wall chases

Looks like a neat job Mr Miller!

Yes, I'd imagine there still needs to be a bit of work to prevent air flow coming down the track and into the box. Surely there's some 'silicon' type material that can be used to fill these awkward gaps (and not degregate the wire)?

893bet wrote: »

I haven't tried it yet but I am assuming** that is not an issue as the socket box and conduit will level it out naturally in the chase and corners when it is pushed in ? And any excess will come out at the sides of the socket and conduit to ensure they are flush with the block work.

**Assumptions the mother of all fuxk ups!! 👼🙀

I'd say your not a million miles off with this assumption.

If I go down the pink plaster route you'd nearly have to fit the sockets and conduit yourself as nice a fella as my electrician is, I doubt he'll stand around for the day while I play with plaster

Was speaking to an Airtightness tester and he reckons that a concrete liquid sealer is the way to go. Simply painted into the chase and socket box. If a product makes concret waterproof well then it's going to be airtight also.

Spoke with a rep for a concrete sealer that might work. He's sending me the data sheet in the morning. PM if you want the details.

Kassandra Icy Peacock wrote: »

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?

Are you satisfied that plaster will stick to the Vana tape?
It isn't the tape that ProClima provide that is specially created to take a plaster coat. Cracks appearing around sockets later would be my worry.

Like your detail, I previously thought of doing the same except putting a strip of AT membrane or solitex all the way up the chase and taping it at the sides. Threw that out the window thinking I'd end up having to put mesh over every chase to make sure no cracks.

I'll hopefully be going the pink stuff route next week. Will see how it goes.

The pink product I'm looking at using is supposed to be applied at 6mm thickness.
This would mean that each chase needs to be 6mm deeper than normal and 12mm wider. Looking at my wall chases today and I can see that the bit used in the kango was marginally wider than the 22mm oval conduit. Plus the depth means the conduit would be proud of the block (I think it should be in line with the blockwork when inserted).

I spent the day widening/deepening the chases myself so I'm still going to use the pink plaster - but it's something that should be considered by others.

Flood wrote: »

Unless you have done the deepening even you are making the electricians job a nightmare. Did you cut the chase to widen it or just kango it?

The electrician made his own job a nightmare to begin with so.
I measured some chases to be 5mm deep at their shallowest. No chase of his was even, absolutely none are plumb vertically and some are actually curved.
Makes for an interesting conversation with electrician next week. I can hear the answer already "ah sure the plaster will cover that".

I took out the curves as much as I could while widening but all I went at are now smooth/even. At start I used a small angle grinder to mark the outside edges of the chases and finished off with a hammer and bolster.
That was taking too long, so I used a heavy duty drill with a hammer action for others. Easier and much neater than kango.

I don't know what it is about boards sometimes, but it's assumed that the self builder or the DIYer is going to fcuk everything up.

Flood wrote: »

Dont be taking me up wrong, I spent over 15 years chasing walls and can tell you now the only way to make chases wider and even is using a chaser and kango with good chisels.
If the chases were only 5mm deep to begin with you should have got them professionally chased out. With the greatest respect and take no offence but widening them and deepening them with any kind of a drill with kango will be very inconsistent.
How were they originally chased?

Originally chased with kango only. No time to get professionally chased as only noticed Friday and want to get conduit in next week.
I can assure you there is only a couple of mm in the difference in the chase. And it actually doesn't matter if they're even or not because the application of the pink plaster can be used to smooth the chase.
Those chases that won't be taking pink plaster are another matter. My plasterer is looking at them today to see of they are deep enough.

893...what I did was a fair bit of work. But my mistake was assuming that the chases would be done properly. You should only be concerned with applying the plaster. You could do that for the chase and leave out the back box...just bed the conduit in to leave a groove in the plaster (don't fix it in place as it is difficult for sparks to pull cable after). Leave the back box out for the electrician to fit. They'd only have to mix a bucket of plaster and work their way around. I'd even say it is much easier for them to level and plumb the boxes when bedding into plaster.
If concerned with the joint between chase and back box, just leave some scrim tape protruding into the box so the joints will knit together.

BarneyMc wrote: »

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'?

Would this work?

On offer in Lidl this week

http://www.lidl.ie/en/Offers.htm?action=showDetail&id=26231

BryanF wrote: »

For what? Garage floors?

The op had mentioned the possibility of using concrete sealer to make chases airtight

I bit the bullet and decided to go with a concrete sealer for the chases. Used SBR sealer, which I mixed with cement at a ratio of 1L SBR to 1kg of cement. It's turns the SBR from a white liquid to a blue emulsion paint consistency (make it easy to see what you've covered).
I was pleasantly surprised by it and while I CANT certify its airtight Id be shocked if it hasn't worked (only the air test will tell). It dried within 30mins solid in a dark grey covering.
I gave the chases one coat and the boxes 2 coats.
I'll attach pics below of it dried

And now I've stuck my neck out and tried it, let the naysaying begin.

SBR is SBR and you can purchase it from a few different companies. It roughly works out at €25 ex per 5L

It comes in 5L & 25L's from the company I purchased from.

You can see in this pic if you zoom it dried almost like a plastic coating on the blocks. You can also use it to water seal bathroom walls and it can be directly plastered over.
It can be used externally in place of thistle bond (internal application only) on mass concrete walls which can then be plastered over as normal.

BarneyMc wrote: »

Thanks for sharing. How did you apply - paint brush? Also, is there any other sealing you'll have to do or is that it for your electrics?

Yes just used a paint brush. You can make it thicker by adding more cement and you can thin it with water (sparingly goes runny quick). That's it for the chases, if I've tape left over I may tape the boxes but to be honest I don't think theres a need.
If your especially anal you could squeeze the airtight silicone (I know it's not silicone) into the screw holes for the socket backing boxes

Have to say it's a piece of piss to paint chases this way.

hexosan wrote: »

Yes just used a paint brush. You can make it thicker by adding more cement and you can thin it with water (sparingly goes runny quick). That's it for the chases, if I've tape left over I may tape the boxes but to be honest I don't think theres a need.
If your especially anal you could squeeze the airtight silicone (I know it's not silicone) into the screw holes for the socket backing boxes

Have to say it's a piece of piss to paint chases this way.

If I thought the difference in airtightness could be measured between the two approaches i.e. pink plaster v blue paint (like something out of the matrix), I'd switch to the paint for my downstairs chases.
As it is, I bought enough pink stuff to do mine and the neighbors place...and I love a bit of smathering anyway.

[Edit: pink stuff = a lot more labor intensive]

hexosan wrote: »

The main reason I didn't want to go with the plaster is the time it takes and stepping on the electricains toes. At least this way it's done in a day and your out of the way.

Can you not do the pink plastering before the electrician comes on site?

The trouble with the pink plaster is making sure you don't have too much in that it bulges out the conduit and cause you plaster to crack after.
I could see the sense in letting the electrician run the wires and the going back and sliding them into the conduct yourself, trowel in the plaster and pushing the conduit in place, same with the backing boxes.

that seems like way more work than just painting the chases***

***but the plaster is known to work and I'm can't say for certain yet if the paint has worked.

BarneyMc wrote: »

My electrician is landing this morning and they'll be chasing the walls soon! Can someone PM me the name of the pink stuff so I don't sound like a wally at the builder's supplier? Also, how much is needed for the 'average' house?

PM sent.

I bought 6 bags and I think that will easily do it for me. I won't waste what is left over as I can use it in the attic space on gable walls where it's harder to reach into corners.
I'm also using it to parge coat from the ceiling down below the line of where the metal ceiling will be installed and if I get a chance will do the first floor where the plasterboard abuts the external walls. And there are the door reveals also (before door frames go in).

Can't remember exact price but I think it was approx €11/bag.

The air is coming from the back of the chase from the cavity of the wall.

Bullocks wrote: »

If you are giving the wall a coat of sand and cement and sealing the conduits either end with the gum i wouldn't bother either

Air will still get in at the back of the socket box.

hexosan wrote: »

Air will still get in at the back of the socket box.

Set them in sand and cement instead of screw fixing them