Hard concrete block. Wall chaser or not?

[1Justin]

Just been to see a new build to quote on. 5 bed domestic, shell going up now. Solid concrete block walls throughout, with block & beam floors. Owner is not sure yet about plastering, I may get a dot/dab, which would be easier for me (albeit a bit crap for the owner).
If it doesn't go that way, there is a lot of chasing concrete. - I've always used my big angle grinder for wall chases, but by the amount of work in this place, I'm tempted to invest in one of those twin disc cutters.
Who uses one, and what brand? - Cheapo ones any good?

 

[Leesparkykent]

If its being plastered without being dot and dabbed then the wall will have to have a coat of bonding. Either way you can just cap straight to the wall as the depth will cover it. 25mm back boxes so wont have to chase them in or 35mm boxes and chase them in 10mm. I tend to go down the 35mm route incase of flat plate accessories, dimmers, feeding the switches,etc. As the wall is either going to be bonded 1st or dot and dabbed the chase for the box doesn't have to be the neatest so I just gun it out with an SDS and chisel bit, takes no time at all realy.

 

[1Justin]

Thanks, I'd overlooked the bonding with the thickness build-up. I'll have a word with my plasterer mate, but that sounds a lot quicker. I'd use back boxes 35 minimum & am happy to grind them round & clear with the scunch.

 

[Skimpy Wan]

Metobo chaser with vacuum are amazing bits of kit. High price tag (around £800), but we'll worth it IMO

 

[Leesparkykent]

Thanks, I'd overlooked the bonding with the thickness build-up. I'll have a word with my plasterer mate, but that sounds a lot quicker. I'd use back boxes 35 minimum & am happy to grind them round & clear with the scunch.

I've got the hang of the SDS and chisel without grinding 1st and get a neat chase for the boxes. I think dot and dabbing then joint and tapping would be a more cost affective way for the builder than bonding and plastering. Also Imo it quicker, tidier and the finish is just as good.

 

[1Justin]

I've got the hang of the SDS and chisel without grinding 1st and get a neat chase for the boxes. I think dot and dabbing then joint and tapping would be a more cost affective way for the builder than bonding and plastering. Also Imo it quicker, tidier and the finish is just as good.

Thanks, I'm going to see if he wants to go ths way (I did mention it on site today).
& changing the subject to something close to my heart,..Disregarding the ease for the builder, dot&dab is a bad way to make a not brilliantly efficient house into a ventilated tent. Have you ever punched through a dot/dab wall for e new socket to find the wind whistling out of the hole? Brick/Blockwork is quite leaky, and when we need airtight houses for efficiency (or even just to prevent winds through the insulation stripping the heat out), dot&dab is a perfect way to screw up that. Solid plaster stops it at least on the inside face, which means it's less likely to blast through the structure.

 

[Leesparkykent]

Thanks, I'm going to see if he wants to go ths way (I did mention it on site today).
& changing the subject to something close to my heart,..Disregarding the ease for the builder, dot&dab is a bad way to make a not brilliantly efficient house into a ventilated tent. Have you ever punched through a dot/dab wall for e new socket to find the wind whistling out of the hole? Brick/Blockwork is quite leaky, and when we need airtight houses for efficiency (or even just to prevent winds through the insulation stripping the heat out), dot&dab is a perfect way to screw up that. Solid plaster stops it at least on the inside face, which means it's less likely to blast through the structure.

Not really given it much thought TBH. With builders/developers it's mostly always going to come down to the bottom line unless they are purposely trying to create a super efficient home. It would have to be some pretty shoddy brick work though wouldn't it for the wind to be howling through? Presumably being a new build wouldn't it have to go through some kind of air permeability testing.

 

[1Justin]

Yes, will need air test. That ought to be the answer for one-offs.
For system houses, they test only one, then I recon the builders do what they like with the rest