Melting shelves.

[Northbeach]

...well they give the impression of melting...I'll explain (hope this is in the correct forum index by the way...?).

I put a series of new shelves up over the weekend (an additional 3 to the 2 already up). These shelves look the part but are a few miles from decent quality (doing most of the house up on a budget etc). I think they are known as 'floating shelves' - you slot holes within the shelf onto two brackets.
Today I attempted to place some old vinyl records across one just above a shelf which had a row of books (the shelves are 1200mm across). As I did the that I could feel the shelf coming off the wall, slowly but surely. I checked the shelf below and that too was slanting.
On the same wall I put up a shelf about 6 years ago (cost me about a quid at the time!) and that has stood it's ground extremely well - even though I used standard red raw plugs and much shorted screws than I do now.
So these days I use strong grey raw plugs (with the arms) and 50mm long screws - this would easily hold the shelves and added weight I thought... not so it seems...The books weren't that heavy, the vinyl perhaps but it's not as though I was going to sit on them.

I've since tightened up the screws in the brackets (4 screws for each of the 2 brackets - the one's with the 'prong') but the slant has returned...if I had a book say then this will go very 'crackerjack'.

Any remedies/pointers? I thought I had advanced from shelf fitting years ago...clearly not!
Help!!

Many thanks.

 

[Deluks]

sevens or twelves? Vinyl LP's are bigger than the average book so the weight would be more forward, and the shelves obviouly aren't up to it.

By floating do you mean that there is no visible brackets underneath? If that's the case then they were probably just designed for photo frames and small ornaments, records are heavy!

Get some proper brackets underneath or lighten the load.

 

[big-all]

sevens or twelves? Vinyl LP's are bigger than the average book so the weight would be more forward, and the shelves obviouly aren't up to it.

By floating do you mean that there is no visible brackets underneath? If that's the case then they were probably just designed for photo frames and small ornaments, records are heavy!

Get some proper brackets underneath or lighten the load.

i agree fully with deluks

think of the leverage on a floating shelve you have perhaps 40mm between the screw and the bottom of the shelve
if the shelve is 300mm if you load up the shelve with weight of say 10kg the leverage would make this about 50kg in the centre off the shelve

so the fixings are being pulled strait out the wall with nearly 50kg of force

exactly in the way that a claw hammer works when pulling out a nail

in a normal shelve the weight is tranfered via the bracket and the load is part pushed into the wall at the bottom of the bracket and part pulled at the top so a 10kg weight will probably excert about 5kg or less pull force on the fitings
not scientific but gives you a good idea how it works

 

[Scrit]

In the past when I used to hang lightboxes, etc for a signmaker we used to specify Fischer S-type fixings rather than Rawlplugs or cheapies and we'd insert two plugs into a hole and use a #8 x 2-1/2in or #8 x 3in screw instead of the specified #8 x 1in. Gives much better pull-out characteristics as two 3in screws in brick will easily hold a 100kg light box in good quality brickwork - at least long enough to get the other fastenuings in! You also have to make sure that you've drilled into brick rather than mortar and that the hole hasn't "spread" as you drilled it. If it's soft cement block then you'll need something like an injection system to hold any weight, but that's probably outside the range of a DIY task.

Scrit

 

[Northbeach]

so the fixings are being pulled strait out the wall with nearly 50kg of force

exactly in the way that a claw hammer works when pulling out a nail

in a normal shelve the weight is tranfered via the bracket and the load is part pushed into the wall at the bottom of the bracket and part pulled at the top so a 10kg weight will probably excert about 5kg or less pull force on the fitings
not scientific but gives you a good idea how it works.

That's all perfectly well explained.
I suppose these shelves are more aesthetic than practical (I tend to forget myself and but into this c*ap every now and again!).

sevens or twelves? Vinyl LP's are bigger than the average book so the weight would be more forward, and the shelves obviouly aren't up to it.

By floating do you mean that there is no visible brackets underneath?

12 inch albums. Yes - brackets are not visible.

If that's the case then they were probably just designed for photo frames and small ornaments, records are heavy!

Get some proper brackets underneath or lighten the load.

I've lightened the load somewhat (the shelves above carring lamps and largish wooden ornaments/flower pots seem ok though...must be the weight of the old hardbacks I placed on there).
As a precautionary plan would it advisable to take out the current 8mm x 50mm screws and replace with 8mm x 60mm screws (but I won't be adding to the weight)?

In the past when I used to hang lightboxes, etc for a signmaker we used to specify Fischer S-type fixings rather than Rawlplugs or cheapies and we'd insert two plugs into a hole and use a #8 x 2-1/2in or #8 x 3in screw instead of the specified #8 x 1in. Gives much better pull-out characteristics as two 3in screws in brick will easily hold a 100kg light box in good quality brickwork - at least long enough to get the other fastenuings in! You also have to make sure that you've drilled into brick rather than mortar and that the hole hasn't "spread" as you drilled it.

I'm sure some went into brick, others mortar (hard to guarantee where you're going to hit I suppose - lecky checked for however).
Some of the mortar/plaster? turned to a black sand as I was drilling - these holes I added a 'squashed' red raw plug. Can the layperson purchase Fisher S-type fixings? Worth getting these in?

I built a bookcase a while ago in a 'cove' of my room - built it against a frame finished with white contiboard - solid as an ox though I had to reinforce a couple of shelves in the middle - wasn't sure of the maximum distance in between reinforcements (I'm sure there must be more technical phrases out there!

Thanks everybody - I wouldn't have guess the problem was due to the weight transferance issue but it makes perfect sense now.

 

[Scrit]

If the hole has "spread" or isn't a good fit on the plug (it should require a light tap to get it in) then I sometimes resort to using a bit of epoxy mortar - I know, a trade product at £25 a tub (builder's merchants), but a tub lasts me ages for all sorts of repairs. BTW Fischer S-type fixings are available from a lot of builders merchants, fastener suppliers (see Yellow Pages) and they've even been sold by Wickes in the past (although Wickes are now doing a cheapo knock-off)

As to sag in Contiboard (15mm MFC - melamine faced chipboard) there's a really useful on-line calculator called the Sagulator on Woodworkersweb.com. Take a look.

A final thought about "invisible" shelves. I've just been putting-in a replacement solid surface kitchen work top and in places there's just been nothing to support the worktop on because the area beneath the top has been filled with appliances. So what I've done is to mount angle brackets in hanging fashion. After the upstands/splash backs went on the brackets were invisible. It should be possible to make inverted "L" form shelves which will carry weight in a similar fashion, although I'd consider adding a couple of dividers between the shelf and its' back. This will reduced the tendency of weight to spread the joint between shelf and back and will all but disappear once the shelf has been stacked with books/records.

Scrit

 

[Northbeach]

So what I've done is to mount angle brackets in hanging fashion.

Not sure what you mean by hanging fashion - are you referring to the L style brackets you would usually use on shelving and fixing them above the shelves as opposed to below? I would have to screw them into the top flat piece of the shellf (say two brackets alongside the invisible brackets - and like you say, these will be hidden by the contents on the shelf? I am reading this right scrit?
The brackets still feel tight in the wall mind - and yes I've used plyfiller for the 'spreading' holes in the past - the plaster is not entirely strong in this house!
Will certainly keep an eye for the Fischer S types also.
50mm ok as a rule of thumb or should I 'upgrade' to 60mm?

although I'd consider adding a couple of dividers between the shelf and its' back.

Sorry scrit - kind of at novice stage in this business! Can you explain adding dividers? Aesthetic reasons (hiding the L frames?) or strengtening?

Many thanks for your help.

 

[foxhole]

Those brackets have about 8 fixing holes , all should be used and screws need to be minimum 60mm, also shelves should be secured to bracket to prevent them sliding forward and increasing the leverage exerted.

 

[Northbeach]

^^ With glue onto the metal poles/inside the slots?
I thought 50mm would suffice (yes there are 8 in total per shelf) - clearly not! They look ok (cheap looking for the price mind) but I've had a few problems with these already.
I guess they have to be so light i.e. you couldn't make floating shelves from solid pine? so they don't collapse any further.
I'll set about replacing with 60mm in the meantime - I suppose I could switch the books on these shelves (many hardbacks) with much lighter DVD's and Cd's.
Thanks.