What Do I Fill Chase With If The Substrate Behind The Plaster Is Brick he Other Side Of The Wall is External?

[Macca Wacca]

Hi there,

I've decided to fill in the chases myself after I hired an electrician to install additional sockets in two rooms which are located on the first floor of a semi detached house.

My original plan was to fill in the chasing with Thistle Bonding and then finish with 2 thin coats of Gyproc Easifill.

Before embarking on this task, I decided to look at the substrate behind the chasing and I can see a bricks. Im reticent to start, as I'm sure I read somewhere that if the internal wall is backing on to an external wall then I need to use cement instead of Bonding.

Second of all, I can see a massive gap at the corner of the wall, where the long section meets the short section of the wall. Also I can see copper pipes at the back of the chase on the short section of the wall. The bathroom is on the other side of the wall.

My questions are:
1) Is Thistle Bonding the correct product to use, where the other side of the wall is external?
2) How do I fill in the large gap at the back, to simply stop the bonding from simply falling away into the gap?
3) Do I need to approach filling in the chase differently if there are copper pipes at the rear of the chase?

Many thanks

 

[opps]

Image 1 and 2 look fine for a plaster base, image 3 looks like it is plasterboard.

TBH, I don't know how well plaster would stick to the foil backed celotex. I wouldn't want to use bonding directly over cold pipes, I have seen them create condensation in the plaster. I guess you could glue some plasterboard in place and fill over the top.

 

[sparkwright]

That was a rough electrician you hired.

Aside from not putting the cables in conduit (there is no requirement for this I should stress) like proper electricians do, he has wrecked that plasterboard wall in picture 3.

As regards picture 3, he SHOULD have only cut into the plasterboard where the wooden studs are, and fished the cable from the hollow sections of plasterboard.

I see no way of simply 'filling' that chase in picture 3 with filler or plaster. You could try expanding foam, but please don't - it would be the ultimate bodge up ever. It will crack very, very quickly.

It needs a plasterboard strip fixing in with screws, but I think you will need to make the chase at least four inches wide, so you can screw a four inch strip of board to the wooden studs, avoiding the cable.

You will need to notch the cable into studs ideally - or leave some notches in the plasterboard strip and fill after.

Did you give the electrician a smack in the mouth?

 

[Wayners]

Bit out of of my area although have worked on some.
I get customers to get a spec for job then follow. I won't take responsibility.
From what I know..
Option one for plasterboard wall is remove plasterboard.
Cut a shallow channel in insulation for cable. Replace plasterboard over.
Option two would be fit boards over entire wall.
Re other walls.
Buy lime plaster repair bags off net.
Really need breathable paint over dried lime plaster.
Other way is to fit insulated plasterboard over the wall to cover plus keeping room warm if required? Plenty of youtube videos on that.
Treat as single skin wall if you don't have a cavity..

 

[Macca Wacca]

I wouldn't want to use bonding directly over cold pipes, I have seen them create condensation in the plaster.

Thanks for the highlighting the potential pitfall if I were to go down this route

 

[Macca Wacca]

That was a rough electrician you hired.

Aside from not putting the cables in conduit (there is no requirement for this I should stress) like proper electricians do, he has wrecked that plasterboard wall in picture 3.

As regards picture 3, he SHOULD have only cut into the plasterboard where the wooden studs are, and fished the cable from the hollow sections of plasterboard.

I see no way of simply 'filling' that chase in picture 3 with filler or plaster. You could try expanding foam, but please don't - it would be the ultimate bodge up ever. It will crack very, very quickly.

It needs a plasterboard strip fixing in with screws, but I think you will need to make the chase at least four inches wide, so you can screw a four inch strip of board to the wooden studs, avoiding the cable.

You will need to notch the cable into studs ideally - or leave some notches in the plasterboard strip and fill after.

Did you give the electrician a smack in the mouth?

I've got a healthy cynicism towards tradies after a couple of bad experiences. If you've seen a post a made a few days ago, I was perplexed about the lack of capping (which I now know isn't necessary, but is a sign of professionalism in a customers eyes) and the lack of cleanup (it was my mums place and could only pop in towards the end briefly on that day), especially as I asked for some dust protection, which was non existent. ... and now this. I digress

Your analysis and approach on making good this wall is the optimum solution for this issue. Thanks

Nope. I haven't given him a smack in mouth or a review. One of which will be done in the near future )

The more you know...

 

[Macca Wacca]

Bit out of of my area although have worked on some.
I get customers to get a spec for job then follow. I won't take responsibility.
From what I know..
Option one for plasterboard wall is remove plasterboard.
Cut a shallow channel in insulation for cable. Replace plasterboard over.
Option two would be fit boards over entire wall.
Re other walls.
Buy lime plaster repair bags off net.
Really need breathable paint over dried lime plaster.
Other way is to fit insulated plasterboard over the wall to cover plus keeping room warm if required? Plenty of youtube videos on that.
Treat as single skin wall if you don't have a cavity..

Thanks for this, concerning breathability for the internal (externally backed) walls. Another piece of knowledge to add.

Coincidentally, this is the first video I clicked on after reading your comment
It further illustrate your point on the need for breathability and problems occuring when gypsum based product is used incorrectly.
Rising Damp? No it ain't - just gypsum! [YouTube]

 

[opps]

I am a little concerned about the cable being in direct contact with the pipes (if they are hot). If he had dug away some of the celotex, it might have been possible to run the cables behind the pipes and add a little wadding to act as heat insulation.

Perhaps you should post the last photo to the electrics sub forum.

As per @sparkwright 's post, the current path of the cable may prevent you from fitting a section of plasterboard in image 3. For the record, I have filled those kind of chases with expanding foam before but you need to carefully remove enough to be able to fill over the top. I use the likes of Toupret Redlite or Red Devil Onetime over the foam. Cracking isn't an issue but if someone pushes their finger in, it will leave an indentation.

 

[Macca Wacca]

Bit out of of my area although have worked on some.
I get customers to get a spec for job then follow. I won't take responsibility.
From what I know..
Option one for plasterboard wall is remove plasterboard.
Cut a shallow channel in insulation for cable. Replace plasterboard over.
Option two would be fit boards over entire wall.
Re other walls.
Buy lime plaster repair bags off net.
Really need breathable paint over dried lime plaster.
Other way is to fit insulated plasterboard over the wall to cover plus keeping room warm if required? Plenty of youtube videos on that.
Treat as single skin wall if you don't have a cavity..

Hi mate,
Would you be able to suggest a suitable product that I can use to fill in the chased wall?

I'm more or less ready to finish this task and put it to bed finally. I've searched for 'lime plaster repair bags' or similar which lead me down a lime plastering rabbit hole around a month ago.

I ended up purchasing this Everbuild Jetcem Plaster Rapid Repair, 6 kg. However, I've seen other products (putty, finish coats etc).
This product is pretty expensive (£15 for 6kg). I've got a chase in another room to fill and I'll definitely need more product to complete the job in one room let alone both

Thx

 

[Wayners]

You can get lime plaster in 25kg bags.
Maybe phone or email local building merchants.
Not familiar with the above product.

Lime Plaster Base (Non-Hydraulic) (25kg)

The coarsest component, typically applied to laths but also onto bare masonry.

www.lime-mortars.co.uk

 

[Macca Wacca]

You can get lime plaster in 25kg bags.
Maybe phone or email local building merchants.
Not familiar with the above product.

Lime Plaster Base (Non-Hydraulic) (25kg)

The coarsest component, typically applied to laths but also onto bare masonry.

www.lime-mortars.co.uk

Super... thanks for getting back to me. Should've probably asked you after my last post, which would have saved me lots of time and headache.

Saying that, any theoretical knowledge and best practice acquired will save me time, money and eliminate any frustrations from implementing wrong approach. Moreover, I was advised by a couple of tradie acquaintances to just short cut the process and use a ubiquitous gypsum based product, as it won't matter in x years time. Expanding foam was even suggested. Go figure . Thx again

 

[jjimjam]

Lime putty isn't very expensive and isn't very difficult to use. The problem is you have to pay for delivery and it's heavy because it has lots of water. It was handy to have some around for smallish repairs. I usually like to do repairs using the same materials as original. So if lime plaster then repair with lime plaster. If cement render, then repair with cement. I feel it works nicely. Normally have to finish off with a powder filler, because I find it difficult to get a perfect finish at the joins. Unlike most plastering products, lime putty lasts forever in water.