Drywall problem

[Notguilty]

Hi, I hope you can help... I have recently had a single skin porch built from Celcon Solar 300mm blocks. The specs require Gyproc Thermaline Super 50mm insulation backed plasterboard on the inside. The guy who was doing the external rendering yesterday suggested I PVA the wall prior to applying the insulated plasterboard by dot & dab. This I did & I applied a little pressure once the boards were on by using a couple of extendable props secured on the opposite newly installed plasterboard wall, if that makes sense...
after 3 hours I removed the props & immediately noticed that the board on one wall was not secure & it didn't take much persuasion for it to come off. The dabs were stuck to the wall but not to the board.
I have spoken to Gyproc who, after much consultation, advised me that I went wrong by PVA'ing the blocks?! Apparently the dry wall adhesive has in it a product which deals with the suction already. As it is not possible to remove the PVA they state the only way I can secure the boards now is to batten the wall & fix it to the battens. Problem is by doing so It will reduce the size of the porch further & we don't have that luxury. New baby has come along & the porch was built to take the pushchair & all the associated clutter.
Has anyone come across this type of problem & found a solution? Any helpful suggestions would be really appreciated.
Many thanks

 

[stevethespreader]

there is no need to pva b4 d&d boards but you can use board addy on low medium and high suction backgrounds, as the addy was stuck to the blocks and not the boards i dont see that there was a problem with the blocks, did you take the boards off to reposition at all?

 

[Notguilty]

Thanks for your reply Steve
Board addy? That's the adhesive im assuming? I have removed the board & scraped the adhesive off the blocks but I haven't attempted to re-fit it due to the conversation I had with Gyproc. I would obviously prefer to attempt another go at dot & dabbing it but im assuming it's going to reoccur. Would that plus the addition of half a dozen mechanical fixings be the solution?

 

[stevethespreader]

addy= adhesive yes because the boards stuck to the wall i dont think the pva is causing you a problem, when i said did you take the board off and reposition i meant did you put the board on then take it off again or move it b4 the leaving the board to set? also did you tap it on with a straight edge? i think you ought to try again look on youtube for a vid on how to put the boards on its easy there should be no need for props let us know how you get on on the second attempt

 

[Notguilty]

No repositioning. The board went on first time & was tapped in using a straight edge. The only reason I used the props to hold it in position was because it did not feel particularly secure, like it was not going to stay on the wall. Maybe I should have left it & it might have been alright. I'll have another crack at it tomorrow & come back to you.

Cheers for now

 

[stevethespreader]

I'll have another crack at it tomorrow

you have nothing to lose by having another go

 

[Notguilty]

Ok so it was suggested by a bloke I know at a plastering school that universal bonding compound should be used rather than drywall adhesive. Unfortunately it seems there are no suppliers in sussex which left me back where I started so another batch of adhesive was mixed up & the boards are on. I have spent the rest of the day measuring & cutting smaller sized boards for the door & window reveals etc & have made the decision to use some kind grab adhesive & wanted to know of any preferred brands or ones to avoid?

Thanks in advance

 

[stevethespreader]

first time ive heard someone say not to use board addy to dot and dab boards, ive just come off a site where they dot and dabbed hundreds of m2 of the boards you are using with it, that universal bonding looks like it does the same thing anyhow so im not sure where the blokes coming from saying not to dot and dab boards with addy i wouldent listen to much to "some" of the teachers at colleges, and i say "some" not all do not have a vast amount of experience, i know that for a fact as i know 2 of them up my way who got a job there after completing there plastering course i also know another who failed his plastering course so they gave him a job mixing the gear up and tidying up so i find it interesting when you say that a teacher says not to use addy to dot and dab, anyhow your boards are on the walls using addy so you must have done it right this time, as for using grab addy im not sure why your choosing to do that but i wouldent use it or recomend it

"EDIT" just to add i wouldent listen to much to what bg says either as it was obvious the pva wasent causing the problem because the addy was stuck to the wall, i reckon you dident get a good fix between the addy and the board the first time round

 

[Notguilty]

Hmmm maybe you're right regarding the initial mix. They're on now & I ain't touching them. As for my question regarding the grab adhesive, the reason I have chosen to go down this route is because there are 9 pieces that needed to be cut & they are different thickness's. The wall below the window, up the side, across the top of the window & front door & down the other side (if that makes sense) is continuing with the 50mm Gyproc thermaline super. The reveals for the door & window don't leave enough room to use the same so I have used a similar product albeit 27mm insulation backed. When measuring & cutting I had to take into consideration the joins & concluded that I would need to allow an additional 10mm or so for the drywall adhesive. This was definately going to cause me problems if I didnt get it exactly right & therefore I decided a grab adhesive would be the answer. After yesterdays nightmare I wanted to try & avoid any further issues.
I appreciate it is not the correct way of doing drywall but time is getting on & there is still so much to do & Im not sure when Im going to get the chance to get back on it.

 

[stevethespreader]

so what your saying is you want to use grab addy to put the reveals on because it will be easier for you to line up with the other boards? you shouldent need to do that but its your house if it falls off then you can always put it back on, but is the reveal level? have you put a level on it? my reveals are bent as hell with twisted lintels ect and on one side its about quarter - half of an inch lower so i had to float it level, if you just stick your board on reveals that is not straight it will look out

 

[Notguilty]

The reveals are reasonably level which Im amazed at so I've just got to go with it & make the best of it.

Cheers for all your help & suggestions Steve.

 

[stevethespreader]

The reveals are reasonably level which Im amazed at so I've just got to go with it & make the best of it.

Cheers for all your help & suggestions Steve.

np good luck