12mm Ply capacity to carry 25kg load

Section62

samal said:

Thank you all
The plywood will be supported at each end (900mm span), one side will be on 1/2 brick wall, the other end will be 3 x 2 inch timber screwed in the wall at 3 location. the room is 900mm wide hence the 900mm size. Fridge will be used on daily basis and has base of 55.3 x 58.4 cm.

Use the 3x2 in the opposite direction, i.e. spanning the 900mm.  Fix the ends to the wall using angle brackets.  This kind of thing -
https://www.wickes.co.uk/WICKES-38MM-ZINC-PLATED-ANGLE-BRACKET-PACK-20/p/164445

Put one 3x2 roughly where the front feet of the fridge go, the second roughly where the rear feet will be.  So long as you install/remove the fridge carefully that's all you'll need.  Most of the support will be provided by the 3x2's, in effect the plywood will be cosmetic/keeping things tidy (only).

MikeJXE

samal said:

The 3x2 will have support each end to the floor, it's abount 1 ft high from the floor.
Yes would move to next thickness if 12mm not suitable.

You didn't say the 3 x 2 would have support to the floor thats why I suggested legs

no matter what ply you use with a 900 span it will still sag with the weight of the fridge and contents 

EssexExile

Remember that if you or a repair man ever need to move the fridge it's going to be very awkward.

Norman_Castle

Supporting it in the middle from the ground would be much stronger. Do you need to keep the area underneath completely clear?

stuart45

I've had the washing machine and tumble dryer on 18mm ply, supported by 3x2 joists or about 12 years now.

diystarter7

samal said:

I want to create a plantform for a fridge (which is 25kg in weight)  using 12.5mm ply, the size is 900 x 600mm. Will the ply hold the weight ?
Appreciatew comments please?

Hi OP

The correct support layout and the fittings of these supports  is the key

Thanks

FaceHead

stuart45 said:

I've had the washing machine and tumble dryer on 18mm ply, supported by 3x2 joists or about 12 years now.

Yes, 18mm ply is massively stronger than 12mm in bending. Instead of being 50% stronger because it's 50% thicker, it's 237% stronger, because second moment of area of a rectangular cross section is proportional to the cube of it's thickness.

The OP should just use 18mm. 

Section62

FaceHead said:

stuart45 said:

I've had the washing machine and tumble dryer on 18mm ply, supported by 3x2 joists or about 12 years now.

Yes, 18mm ply is massively stronger than 12mm in bending. Instead of being 50% stronger because it's 50% thicker, it's 237% stronger, because second moment of area of a rectangular cross section is proportional to the cube of it's thickness.

The OP should just use 18mm. 

The OP doesn't need to use 18mm though - just use the materials more efficiently.  As I described - and as stuart45 has done - if the 3x2's span the longer dimension they will provide all the support needed, the plywood then isn't being used in a structural role and doesn't need to be that thick.

stuart45's arrangement is not only taking the heavier dead weight of the washing machine (vs fridge), it also copes with the dynamic loading of the washing machine in the wash and spin cycles.

There's nothing intrinsically wrong in putting the 3x2's along the side walls and using the plywood as the main structural member - it just isn't the most efficient use of material, and given today's material costs, economy in use is more important than ever.

grumbler

IMO, a piece of 38mm laminated worktop (from Freecycle preferably) is the best material for this job. For 90cm span it doesn't need any extra support and will look nicer than anything else.
More expensive solid wood is fine too.