Wall fixings...

[Mike Dodd]

Ok, this might sound a rather basic question, but its based upon years of experience of inadequate wall fixings...

I'm about to mount two large computer desks on battens in our toy room (cf. "Home Office"), with much of the weight to be taken by desk legs.

The desks will occupy the complete length of an outside wall of the room (3.6m), and one side is also an outside wall, the other is a stud wall. These two ends of the table will need battens approx 1m in length (excessive length due to the curved ends of the desks).

Now, the interior walls are plasterboard over timber frame, so I'm just going to find where the studs are and screw the battens into those - that much is straight-forward.

Where I've come unstuck in the past, however, is with the exterior walls. These are dry-lined, plasterboard blob-bonded to cement block (with an exterior brick wall - but I'm hoping not to go quite that far!). B&Q et all sell various devices for various wall types, e.g. plasterboard fixings, concrete block fixings, etc.

Now, I think I'm right in saying that plasterboard fixings are not appropriate here - I need the fixing to go into the blocks behing the plasterboard. BUT, the block fixings that I've seen are intended for direct mounting (i.e. the head of the fixing is flush with the block - I've got the small issue of 12mm of plasterboard + air gap in the way.

In a case like this (where I don't want to rip the plasterboard off the wall unintentionally) any suggestions as to the "best" wall fixings? (plus, if possible, a URL so I know what you're referring to)

Mike

[James Amor]

Mike,

How about using sleeved anchor bolt:

or a thru bolt: ?If you got one long enough to go through the plasterboard & air gap, with the expanding tip in the blockwork....?

Might work (might not.....!)

James

[Set Square]

It's not easy - unless you happen to be lucky, and drill in a place where there's a blob of adhesive - in which case normal rawlplugs are ok.

You can drill right through into the blocks and insert a parallel sided rawlplug (the sort which doesn't have a flange on the end) plus long screws. The trouble with that is that it tends to bend the plasterboard as it tries to pull it closer to the blockwork.

For light fixings, you can use special Easi-drivers - such as

- which screw into the board, and then take a smaller screw to hold the object in question.

For heavy fixings, the best bet - in my opinion - is to cut away a small pice of plasterboard (maybe a 1" diameter circle) and use some solid packing (e.g. short length of broomstick) behind your heavy object - which is then firmly attached to the blockwork.

[david lang]

Hi Mike

I reckon you only have two choices here because fixing to the plasterboard won't be strong enough and if you fix through it, when you tighten up the fixings it will bend/crack the board.

One is to build a frame to take the weight of the desk and fix that to the plasterboard - maybe with 'no more nails' or similar just so it doesn't tip forward or rack sideways. The weight would be held by the frame between floor & desk.

Second option as I see it would be to carefully mark the position of the battens along the wall, then cut out a strip of plasterboard so the batten is recessed in and can be fixed direct to the brickwork. Very strong and easy enough to make good if you ever decided to remove it. You would just need battens 12mm or so thicker.

HTH

Dave

[Mike Clarke]

80mm hammer in wallplugs like Screwfix 13953 or frame fixings (17286) or other lengths to suit did the trick fine for me when I put a shelf on a dry lined wall recently. Don't hammer them hard though or you could push the plasterboard back towards the wall, just tap them in gently until they line up with the surface and tighten up the screws with a screwdriver.

[Mike Dodd]

Bloody Hell James!!! (Don't worry, I know him)

Talk about the proverbial sledge-hammer to crack a nut!

I think the real issue here is like others have said - the risk to distorting the plasterboard around the fixing.

Re: other suggestions... I don't like the idea of chasing a channel out of the plasterboard (yes, it does sound the best solution, but very messy), I might give the extra-long plugs a try and see how they cope, or drilling say 25mm radius holes and using dowels etc (thanks, Set Square).

[john]

It's a real problem - perhaps Plasplugs can get their mind around it. Many items have keyhole slots that need to have a screw tightly fastened into the wall - yet with nothing to tighten up to many plugs will not open and grip.

John

[Lobster]

I think this is easier to solve than other people are making out.

Mark up the position of the holes on the wall and drill deep holes through the plasterboard, air gap and into the wall; I say 'deep' because when you put the rawlplugs in, you're going to want the loading to borne by the blocks, not the plasterboard. Don't put the rawlplugs in yet though.

Next, procure yourself a tube of glue (something like: and inject this at an angle into the holes, in all directions - the object being to pack as much as you can into the dreaded airspace around your hole. If it gets *down* the hole you'll need to fish it out with a bit of wire or something.

If it's awkward to get the glue in, or you're not confident it's getting where it should, an alternative would be to drill a few more holes in a circle around the existing hole, at an angle, pointing in to the existing hole, and inject down those as well. When you see glue emerging from other holes, you'll know the underlying airspace is now packed with glue. The new holes will all be hidden by the batten.

Finally, insert standard rawlplugs and leave it alone until the glue has set. At that point you'll be able to screw on the battens with impunity, as you've eradicated the airspace directly underneath.

David

[david lang]

Mike Dodd wrote: I'll raid all the local Homebases for all

IKEA have a huge range of table legs very cheap. Worth a look?

Dave

[Mike Dodd]

Hmmm, but worth a trip? (gah, only ever been once... Warrington, day after New-Year's day, a few years ago, absolute hell on earth!)

...but might have a look online, anyway :)

[Mike Clarke]

Use a fixing that expands by pulling a wedge up through the plug like Screwfix 79612. Use it to temporarily screw a small piece of plywood to the wall first to set the plug. Then unscrew and discard the ply. Works OK but be careful not to push too hard on the screw as you remove and replace it. Be prepared for a fairly high wastage of plugs though, I've found that the wedge sometimes just spins round with the screw and doesn't pull up to expand the plug :-(

Metal hollow wall anchors (Screwfix 72229) are good for this too, if you use the setting tool (12429) instead of a screwdriver to expand them.