Bouncy dot and dab

[liam546]

I have just dry lined my entire downstairs. All walls were stripped back to brick and I used a new safeguard drygrip adhesive to 'dot' n 'dab' plasterboards to the wall. I used this adhesive instead of usual dry wall adhesive to combat any damp patches coming through.

The downside to using this adhesive is that I'm not able to put anywhere near as big dots on the board and this has left some boards quite bouncy or springy in some places where there are voids between board and wall. The boards do appear solid to the wall and I'm not so worried about them coming away.

My concern is though that if the biards are too bouncy once plastered could the walls potentially easily crack? [/code]

 

[roy c]

If the walls are "springy" then it makes me wonder if the dots have stuck to either board or wall ,How many dots did you put on each board what was the surface of the wall like that you dabbed them to. Did you dot and dab the bathroom that you are tiling? Ask your plasterers what they think of the walls you did they should know what to do...

 

[liam546]

Thanks for the reply. I used possibly 15 dits per 8x4 foot board. Perhaps each dot was 8 inches apart. My walls are quite uneven and so I think you are correct when you say some of the dots haven't stuck to both board and wall.

For areas that are bouncy I am trying to pack out with stixall but some areas are still bouncing a little. Not having done this type of thing before I just wondered if boards had to be completely solid with no movement or bounce before plastering. I'm worried if I lean or crash into the newly plastered wall the board will bounce behind and crack the plaster.

I'll ask my plasterers and yes I did dot n dab bathroom but this was with conventional drywall adhesive and with much larger dots so there is much less and nearly no movement

 

[roy c]

15 dots is no where near enough to spot a 8'×4' board to a wall. If you put them every 8" then you would have 13 rows of 7 dots which would work out at 91 dots. There should be no movement at all when the board is stuck on right, if there is you will have problems in the future,,,

 

[liam546]

Rethinking it I have anywhere between 15 and 25 spots on each board. The boards are solid to the wall now but with some bounce in places.

What about if I drilled small holes into the bouncy areas and then pumped a load of stixall in behind to pack it out and stop the bounce?

 

[noseall]

We always fix with solid lines of adhesive.

One complete bead all around the perimeter of the board followed by two more evenly spaced vertical lines of dab.

What this means is that there will be no 'chimneying' of air passing up behind the boards. We also fill solid around any back boxes.

I was once astonished at how much air movement there can be in a house on a very windy day. Air can move between floor joists and up behind skirting boards and travel up any voids at the back of the boards.

I watched as some errant polystyrene insulation balls were being puffed out of some socket gaps in a poorly fitted house.

 

[noseall]

What about if I drilled small holes into the bouncy areas and then pumped a load of stixall in behind to pack it out and stop the bounce?

It will work (to a degree) with ex-foam.

 

[clive12345]

I agree with noseall .
We had some flats to plaster, the dabbers forgot to continuous dab
in various places. We used expanding foam ,it left a solid board .
If the existing boards are weakly attached ,i suppose there is a chance the foam ,could move them. Perhaps you should experiment ,do three or four holes,then leave them overnight .

 

[liam546]

Thank you for the replies. This safeguard drygrip adhesive that I've used is extremely expensive and so doing continuous lines would have been very expensive. I understand fully reasons for doing it though. The adhesive is £14 for what is effectively a tube no bigger than what you'd fit in a cartridge gun.

I am using about 3 tubes per board which is £42 in adhesive per board. I think id have had to use double the adhesive and double cost to do the whole perimeter of the board. I'm using this adhesive rather than normal dry wall due to this adhesive being designed for damp issues (which I had).

I will drill the holes where's there's bounce and use the adhesive expanding foam and try that as you've suggested. The boards do feel pretty strong to the wall so hopefully the foam won't push the board away from the wall.

 

[3DGuy]

I see from the thread you said you have done the entire downstairs. I assume that's finished not as in, in progress...

See how the boards are, I just read it was £14 per tube. It must have cost a fortune to board out the entire downstairs...

Just a random Q and if it's all done now then ignore this except you can reply if you like as I'm curious. If there was damp, surly that was treated. however rather than sticking the boards to the wall, could you have used thin batons? and then screwed the Plasterboard to that?

Just curious for the dab route when there was damp is all.
Hope the bounce does go, or the foam helps.

Just looked that adhesive up. One point is this..

◾Accommodates natural movement of the wall.

It's not that which is causing the moment? Have you tried a little patch of the adhesive where you can see it? on a plasterboard offcut to see how it is when it dries out? That might be useful to see if there is flex in it.

 

[liam546]

I had rising damp on a few downstairs walls. Damp causes such as guttering and soak aways have been improved and I have had a new DPC installed. My walls are very uneven and the bricks used in my house are like air bricks and are very difficult to get a true fixing too. With it difficult to get a proper fixing and the fact my walls are really uneven I thought this solution offered by safeguard where you use there dryshield product (cream to paint the bricks with to stop salts coming through to plaster) and the the cream acts as a primer for the drygrip adhesive was a good one.

The biards are solid to the wall but as my walls are uneven and the adhesive was so extensive I couldn't use as much as I'd have liked on each board. It did cost several hundreds of pounds to do the whole downstairs like this yes.

The adhesive when dry sets fairly hard but there is a small amount of flex in it. Kind of rubbery. Certaibly disent set like cement or normal dry wall.

I think my only option now is too drill holes where the bounce is and fill with foam adhesive or stixall as the guys have suggested.

 

[liam546]

To be honest I don't know how much bounce/movement/flex in a plasterboard is acceptable in order for skim to go on ok and not crack or cause mad problems.

 

[OwainDIYer]

To be honest I don't know how much bounce/movement/flex in a plasterboard is acceptable

None, IMHO, which is why I hate dot n dab,

Owain

 

[liam546]

I assume the consequence of having boards that are not solid is that the plaster could crack if walls are leant on.

 

[ree]

I'm with the haters of D&D - given that it has its uses in some remedial situations, and in new work(quicker & cheaper) but as a retro method it can create all kinds of knock-on difficulties. It can also sometimes take longer than traditional methods.

FWIW: i think the day is fast approaching when, after all these years of fixing D&D, it will start coming back to bite in the ass.

I just hope that someone somewhere will be training solid plasterers?