On 14/09/2013 00:04, Dave Plowman (News) wrote:
In article ,
SteveW wrote:
Surely it's far more difficult fixing boxes to the wall good and square
than cutting holes in plasterboard to do the same thing?

Not in relatively soft blockwork. I wasn't bothered about mess and just
used old, sacrificial router bits in my router to rout out perfectly
flat bottomed, square holes for boxes and nice, straight edged chases
for the cables at the same time.

Ah. Might be with blockwork. Was more thinking of bricks. Ie, old house
rather than new build.

I thought that was the way you were thinking. As it happens, our house
also has a brick inner leaf, it is only the extension and the
conservatory that have internal blockwork. It was when I was building
the conservatory that I used this method.

SteveW

On Friday, September 13, 2013 6:56:34 PM UTC+1, Piers wrote:
On 10/09/2013 15:40, sm_jamieson wrote:

On Tuesday, September 10, 2013 2:25:08 PM UTC+1, wrote:

Hi Guys,







I have a quick question. I am in the process of converting /restoring an old victorian house. Taken a lot of walls back to brick and run in new plumbing and electrics. My question is.......



how would you dryline (using foam) around new electrical back boxes ? would the foam give you the depth?







Not sure if anyof you will get this message but any advice is appreciated.







cheers







Ben



The foam would give you up to about 25mm gap I would say. The trouble with fitting back boxes first is getting the holes cut in the correct place - can be done though. A trick on DIY SOS I saw once was to put the plasterboard against the wall with backboxes and "bang" it to create an impression of the back box.

I tried this and it sort of works. I also tried putting ink on the back box to mark the plasterboard, which sort of works too. But it never fits quite as well as you expected !

The difficulty with fitting the boxes after, especially if the wiring is in place, is getting the box into the hole whilst the wires are blocking the hole. The best thing I found is to cut into the plasterboard to give more play in the cables, then fill this with some plaster afterwards.

I'm not sure how the pros would do this type of job.

If the wall/PB gap is enough you can fit hollow wall boxes of course.



Note: if using foam, include some mechanical fixings near the top for safety in case of fire, etc. You can get some special fixings for this purpose. I've not used them but I assume they are like hammer-in frame fixings but with a broad shallow head on top (I've just visualised Stewie from Family Guy).

Simon.





Do you have a link to the sort of fixings you're talking about?

Sorry for the delay, just seen this reply.

http://www.twistfix.co.uk/insulated-...rboard-fixings

Simon.

On 16/09/2013 15:43, sm_jamieson wrote:
On Friday, September 13, 2013 6:56:34 PM UTC+1, Piers wrote:
On 10/09/2013 15:40, sm_jamieson wrote:

On Tuesday, September 10, 2013 2:25:08 PM UTC+1, wrote:

Hi Guys,







I have a quick question. I am in the process of converting /restoring an old victorian house. Taken a lot of walls back to brick and run in new plumbing and electrics. My question is.......



how would you dryline (using foam) around new electrical back boxes ? would the foam give you the depth?







Not sure if anyof you will get this message but any advice is appreciated.







cheers







Ben



The foam would give you up to about 25mm gap I would say. The trouble with fitting back boxes first is getting the holes cut in the correct place - can be done though. A trick on DIY SOS I saw once was to put the plasterboard against the wall with backboxes and "bang" it to create an impression of the back box.

I tried this and it sort of works. I also tried putting ink on the back box to mark the plasterboard, which sort of works too. But it never fits quite as well as you expected !

The difficulty with fitting the boxes after, especially if the wiring is in place, is getting the box into the hole whilst the wires are blocking the hole. The best thing I found is to cut into the plasterboard to give more play in the cables, then fill this with some plaster afterwards.

I'm not sure how the pros would do this type of job.

If the wall/PB gap is enough you can fit hollow wall boxes of course.



Note: if using foam, include some mechanical fixings near the top for safety in case of fire, etc. You can get some special fixings for this purpose. I've not used them but I assume they are like hammer-in frame fixings but with a broad shallow head on top (I've just visualised Stewie from Family Guy).

Simon.





Do you have a link to the sort of fixings you're talking about?

Sorry for the delay, just seen this reply.

http://www.twistfix.co.uk/insulated-...rboard-fixings

Simon.


Not seen these before - thanks.

sm_jamieson wrote:

Piers wrote:

Do you have a link to the sort of fixings you're talking about?

http://www.twistfix.co.uk/insulated-...board-fixings=

The option of installing plasterboard by SDS hammer strikes me [pun
intended] as rather violent