Floating Countertop Experiment

[Coddey]

I’m experimenting with the installation of a floating countertop / basin. At the top of the picture are the brackets I’m considering using. Below that is my ‘test rig’ screwed into the garage wall (same blocks as used in the bathroom). At present I have just over 28kg sitting on these brackets using 4 of the 8 available fixing points. There is some mild flex if you push down on it.

When installed in the bathroom, the countertop, basin (including water), taps, waste, etc combined will be around 15kg.

How much flex is acceptable and how much weight should I allow for anyone pushing down into the basin whilst washing?

Once again, as usual with my questions. Any advice, ideas, previous experience welcome

 

[ShaunCorbs]

Should be fine I would use resin anchors though eg

NYLON SLEEVE WITH ALIGNMENT COLLAR FOR CHEMICAL RESIN ANCHOR STUD M8,M10,M12,M16 | eBay

M5,M6,M8,M10 A2. M4,M5,M6,M8 A2 Stainless Steel. M3, M4, M5, M6, M8. For use with injection resin and threaded studs. Allows the resin to push through the perforations and form a bulb within hollow substrates.

www.ebay.co.uk

https://www.NoLinkingToThis/p/rawlplug-r-kem-ii-styrene-free-polyester-resin-300ml/32863

And m8 studding etc

It’s only a basin so your chances are good as for deflection I would be surprised if it’s more than 10mm when finished

Depends how strong / thickness the brackets are

 

[Coddey]

The shelf will span 35cm and be 22mm thick, so there shouldn't be any deflection. The four screws holding the brackets are set in Fischer 8x30 duo plugs left over from my kitchen install. There will be eight in 8x40 plugs in the final fix (assuming I use plugs and not resin). So it will be down to the brackets which are claimed to support 40-60 kg each. Although I wouldn't want to stand on them fixed 20 feet up the side of a wall!

 

[ShaunCorbs]

If you can get into the solid part of the brease block should be ok but if you hit a hole plugs won’t do

 

[oz-plumber]

Longevity, plugs won't do the trick.
And your only using 40mm plugs. Depending on whats on the wall surface of the bathroom, you may only be doing into the blocks by 25mm.

Drill some descent depth holes and use Resin or Chemset to fix allthread into the wall and fix the brackets to that.
With Chemset, I doubt you will need more than 2 fixings in each bracket.

At least with Chemset, when the basin falls off the wall it will bring the blocks with it.

 

[Coddey]

I’m going to change the brackets and use resin with M8 studs. The existing brackets will only accept a 5mm diameter fixing, if I open the holes out to 8mm for M8 it will compromise their integrity.

Had I used 40mm duo’s they would have gone into the block behind the plaster. I originally opted for plugs as my kitchen half height wall units weigh in at 30Kg empty and nearly 40Kg loaded with cans. They’re held up with 4 x 30mm duo’s (they were the plugs I was advised to use by the majority of kitchen fitters).

Even considering the cantilever effect on the floating basin, it works out that the total load at the furthest edge would not exceed 25kg when full of water.

An interesting anecdote. I recently looked at an installation with a 50mm marble top measuring 600mm x 400mm, with a 10kg basin and two weighty taps. The total weight exceeded mine by a country mile and that was fixed in the same cement blocks as mine with 8 x 30mm brown rawl plugs. It was put in over three years ago and doesn’t even flex.

Nonetheless, belt and braces at very little extra cost is a common-sense approach.

 

[oz-plumber]

I doubt the integrity of the brackets will be reduced if drilling holes to 8mm.

The brackets weren't the issue, the wall plugs were

 

[Coddey]

Opening out the holes to 8mm would break through the edge of the bracket, hence if using M8 studding I need to change them.

I'm going to keep the dry fit countertop in the garage loaded with 50kg until such time it comes away, or I deem it a safe option for future works

 

[Ben-gee]

The bigger holes won’t break through if you keep the current hole edge as your edge, ie re-drill with a different centre point. Sometimes you have to think differently to solve a problem.

 

[Coddey]

The bigger holes won’t break through if you keep the current hole edge as your edge, ie re-drill with a different centre point. Sometimes you have to think differently to solve a problem.

I changed the brackets in the end. Used R Kem II and M8. Would have looked nice, except I've now got another issue with the plaster for tiling. Never bloo%y ending, this job.