No good will come of it.....

Sep 30, 2013 20 Replies

Popped into a new build site today to drop off a handful of business cards to the sales office.



Got chatting with one of the builders & asked him about walls etc.



Outer skin brick, inner skin lightweight block with dot'n'dab, steel lintels above windows.



What with people increasingly wanting huge flat screen TV's, designer radiators, ornate curtain poles, large mirrors etc fixed to the walls, it's becoming a bit of a minefield.



Do architects ever think of these things?


Is plaster board usually dot'n'dab? Why is that better than simply plastering the blockwork?

It's only "better" where time is money ...

Sorry, I meant that I assumed it was cheaper, but how come?

You have the cost of the plaster board, and lugging it around, then cutting it up, scrimming the joints, etc etc

Versus lugging around plaster and water, mixing it, then trowelling it on.

Both need a skim coat.

Its very common, mine is like that but it doesn't create a problem other than needing long screws, (4.5" for my wall cabinets).

Its easy to drop a wire down between the blobs if you want a new socket.

On Monday 30 September 2013 19:33 GB wrote in uk.d-i-y:

Nope. Many new builds just have the joints taped and filled and painted. I've lived in two such places and worked in several places that are done like that. In fact I think my current house is only place I have even seem skimmed PB first hand!

cheaper and faster

Last year I worked on a newbuild that used bonding and skim coat. The cost of this was cheaper than dot and dab but there was an extra two/three weeks installation time than using dot and dab. That's down time when you want to sell a house.

As Andy said "It's only "better" where time is money ..."

with unskilled plasterers, aye..

Does that "installation time" include the drying time for bonding and skim?

Quite if you can't whacka coat or two of Magnolia over it that's more delay...

Surely someone has invented magnolia-coloured plaster by now? Coloured render's quite common for external use.

Owain

Quicker, cheaper, no drying out and much easier to get a defect free finish, also marginally reduces U-value. But I'd still prefer wet plastering which also makes for a more airtight wall - when the requirement for air testing new homes came in, the advice I passed on re drylining was to rough skim the wall first to seal all the micro gaps and pores.

No, I remember my fireplace falling to bits when an old fashioned tv bracket was fitted.

Brian

I had to fix one of those to a wall in a GFds hose.

The half brick I was drilling into fell out into the gadren.. all the was was a single 4" brick skin..and that was made of rubble and mortar minus most of the cement.

Yours is the only reply so far to mention the U value. I don't know how much it does reduce it by, but Building Inspectors in the UK seem to think that it's significant. When converting a built-in garage into a kitchen, I was tight for space - and the extra space taken up by dot'n'dab PB compared with plastering the blocks would have meant that I couldn't get the desired kitchen units in. I had a hell of a job persuading the BCO to let me do it my way.

Its not a huge gain on a well isnulated room. It is significant on an older property with a solid brick wall.

BCODS have a book of 'stuff that is instantly able to meet te regulatiuons' In order to prive that what you want to do that isnt in te book will ALSO meet regulations, the onus is on you tpo prove it.

Which is why I spent a shitload on an energy analysis of this house so that I did NOT have to put in double glazing.

For a brick outer leaf, block inner leaf, with insulated cavity, the difference is only 0.02 W/m^2K between plastered and D&D according to

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The downtime was mostly the drying time.

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