DottNDab nightmare help - will my fixings work?

[Matt_Carter]

Hello, sorry I’ve not been down at the space I’ve been upgrading my flat and it’s pretty far away. I hope to restart in the new year.

I do have a question if anyone can help me about plasterboard fixings, dott n dab walls and how to know something has worked;

My goal is to put these twin slot shelving units up on my wall, they’ll hold a lot of books and hopefully a desk so about as much weight as you’d expect to put on these things, + cylical loading / unloading of someone leaning on the desk perhaps.

I had assumed (wrongly) that this wall would have wooden battens, and approached it with that mindset. I did purchase a stud detector, which I’ve since learned is more of a density detector. I tried to find the studs, but they seemed inconsistently placed, of varying thicknesses and the detector didn’t find a continous stud vertically… I put lots of holes in the wall anyway though, as I wanted to progress the job.

Something wasn’t sitting right however, as none of the dust had any wood particles, a number of the drill sights went through the inital plasterboard then immedaitely gave way suggesting a cavity rather than the batton the detector told me was there. As the wall is exterior, in a 92 build house I learned from chatGPT it’s most likely to be DottAndDab.

That’s okay i thought, i have plenty of fixings, i ordered some dott+dab specific fixings, put two in per batton (50kg rating each) and a number of the other metal splay fixings that you pull out with a gun.

however, with the added depth+cavity of the metal batton (a U shape with the two arms of the U pointing at the wall) the action of tighenting the screw has pulled some of these fixings out until it hit the bottom of the U and only then do they stiffen up while tightening.

Some of the fixings as well just don’t seem to have worked, as the screw definetely threads, i can feel the resistance and I can’t pull the screw out the wall with plyers, but it never stiffens or tightens, just constantly spinning.

Some of the fixings have worked as I expected them too, and become very tight.

How many do you think I can get away with that have potentially failed? Have the ones where the screw is spinning definetely failed? Is this project too risky to put on a DottNDab wall to begin with, even with good fixings?

I could tear it down, and reinstall it on an interior wall I have now confirmed is definetly got timber framing inside, but it would leave an Insane mess of this wall…

[Charlie_Woodbridge]

Hey Matt!

Bit of a late reply here, hopefully you’ve got this sorted? If not I’ve got some pointers below.

It’s always possible to get good fixings and hang heavy items in a dot and dab wall, it just takes a lot more effort than a solid wall. Hopefully the below helps and answers some of your questions…

A few alternative methods for fixing into a dot and dab wall, listed from least to most effective…

• Pig tail fixings - these screw directly into the plasterboard and create a solid point to fix to within the plasterboard, they are prone to rip out with too much pressure
• Fischer plasterboard fixings - similar to the above but higher quality
• Locate the “dots” and the “dabs” and use these as solid the solid fixing points for your rawl plugs (this does of course hinder where you can have fixings and put the U shaped supports)
• Fix a patress to the solid blockwork behind - cut back the plasterboard the width of the U shaped upright, fix a solid timber or ply patress to the blockwork, then use this as a solid fixing point for your screws - effectively eliminating the void behind the plasterboard (pic below for reference)

With regards to moving this shelving set up to a more solid wall, this would of course be the most secure and safest way - it’s easy enough to refill, sand and paint the dot and dab wall you’ve drilled into. But if you’re set on using the dot and dab wall and willing to spend the time and effort reinforcing the fixing points where the screws are going, it’ll still be a solid construction.

Hope this helps in anyway man!