A question of weight...

[Marcus Fox]

I have fitted some shelves into an alcove between two chimneys. The shelves are approx 70 cm across and 30 cm deep. The shelving material is combiboard (sandwiched plywood) about 18mm thick. These rest on battens 2 cm x 4.5 cm x (depth/width) which are screwed to the wall on either side and at the back with nine screws (approx 5cms long) in total (3 x 3).

Would these shelves support a sustained weight of about 60 kg? Reason I'm asking is I want to put a 10 gallon fishtank on one of them and I don't want it coming down for the obvious reasons. Any suggestions on reinforcing them if needed? Or would it be best to just put them on the floor, or bottom shelf (resting on a couple of bricks to reinforce) to raise it above the skirting?

Marcus

[Dave Jones]

"Marcus Fox" wrote in message news:xJq6d.3$ [e-mail]...

All I can suggest is to load the shelves with something of equivalent weigh for a test run (something unbreakable!)

and leave it for a week.

[gribblechips]

I think that it would be OK if the shelf is supported at the front as well as the back and ends. I have put up a similar arrangement (18mm ply in an alcove, fish tank on it) but the front is of the shelf is glued into a rebate routed in a 2x2 so that they are flush on the top edge. and the ply edge is hidden. This front support is fixed onto the end battens.

I`ve stood on it while decorating and I`m a fair bit more than 60kg

Bear in mind that a glass tank will tolerate much less flex than a row of books.

Cut a hole in the shelf too so you can run pump and light cables neatly behind the tank.

[Set Square]

I think that the shelf itself is ok, But it needs to be better supported - particularly at the front.

First the back and sides: I would use a minimum of five screws for the rear batten - either 2.5 x 10 or 3 x 10 (rather than your 2" screws) to make sure that a goodly length goes into solid brickwork. I would use longer screws at the sides too - but 3 each side is enough.

Without additional support at the front, the shelf is in danger of sagging in the middle. I would support it with a length of 1.5" steel angle, going right across the alcove with the ends supported by the side battens. If desired, you could put a lip downwards from the front of the shelf to hide the angle.

[N. Thornton]

I think that could be a recipe for disaster. Load it with double the target weight, if it takes that for 5 minutes it'll be fine with 60kg. Watch your toes though.

Regards, NT

[Marcus Fox]

There is nothing to screw the front support on to, as the side batten supports run right to the depth of the chimney. The batten at the back wall is screwed to the back wall. It is fairly tough to flex the combiboard, although I haven't yet tried it with 60 kg. I am also at a loss with what to test the shelf with, I have about 40 kg of barbell weights, but not much else, no cinder blocks handy.

Marcus

[Ian Stirling]

Until the water gets to it. Expecting the surface to remain dry at all times may be optimistic. Silly things like aerosols of water from bubbles breaking, or stuff down the back from emptying the filter, or a slow leak in the tank from a crack.

[Set Square]

Why can't you support the front re-inforcement off the side battens - with a halving joint, or something?

Actually, if you screw a length of angle to the underside of the front edge, it doesn't really need to be supported - but it will still stop the shelf from bending in the middle. In other words, it won't be holding the shelf up (the battens are doing that) - but it *will* increase the bending stiffness.

[Marcus Fox]

Where can I get this angle from? Do they cut to size or would I have to do it myself?

Marcus

[Set Square]

You can get it from a steel stockist. Do you have a branch of Metal Supermarket near you? They are apparently happy to sell small quantities.

Otherwise, find a bit a scrap. I've got quite a lot in my garage which came from old metal bed frames. If I were doing it, it'd get a piece of this, cut it to length with a hacksaw, drill and countersink some screw holes in it, paint it and screw it to the shelf.

[Rick Dipper]

I have a 100KG fish tank on a shelf I constructed in a similar way. My wall batterns are 34x34mm, and I have one along the back to stop bending. The screws are long enough to be in the brick, and not just the plaster.

The big issue is bending of the shelf, as the tank has to be supported accross its whole base.

Basicly the G/F & I + the kids all sat on the shelf, with a combined weight of 200kg it was good, so on went the fish tank.

Rick