How to prevent sagging shelves

[Charlie Woody]

I am currently making a wardrove and bookcase for my daughter, both of which will have some shelves. The carcases and shelves are 18mm blockboard and I will be adding 30mm Tulipwood lipping. The lipping will be rebated for the blockboard to hopefully prevent the shelves sagging. The wardrobe shelves will be 500mm wide and the bookcase 600mm wide.

Knowing my teenage daughter both will end up pretty full and therefore heavy.

My question therefore is should I put the lipping on the back as well as the front of the shelves?

 

[adidat]

it wouldnt hurt. why not make the shelves out of solid tulip then they would be stronger.

adidat

 

[barkwindjammer]

Vertical dividers ?

 

[Charlie Woody]

Hi Aditat

When I purchased the materials I had not fully thought through the shelf design so I got enough blockboard for the shelves and enough tulipwood for lipping only. So will do as you suggest and lip front and back.

Hi barkwindjammer

I don't think my daughter would like the vertical dividers as she wants the full width of the shelves for some of her stuff.

Thanks for your help guys.

 

[Dibs-h]

I am currently making a wardrove and bookcase for my daughter, both of which will have some shelves. The carcases and shelves are 18mm blockboard and I will be adding 30mm Tulipwood lipping. The lipping will be rebated for the blockboard to hopefully prevent the shelves sagging. The wardrobe shelves will be 500mm wide and the bookcase 600mm wide.

Knowing my teenage daughter both will end up pretty full and therefore heavy.

My question therefore is should I put the lipping on the back as well as the front of the shelves?

I think you'll be fine to be honest. Blockboard is quite strong stuff - test it out! Place it on some supports (offcuts are fine) at the same spacing as the shelves are intended to be and place around 5kg evenly spaced - I'd be very impressed if the deflection was noticeable.

I have some 8mm (or thereabouts) ply shelves up and they are quite heavily loaded with books - and no issues there. Been up for years.

HIH

Dibs

 

[Charlie Woody]

Thanks Dibs I'll try that.

 

[woodbloke]

...or you could use the sagulator which will take all the guesswork out of it - Rob

 

[mtr1]

At 500mm wide(that's just 20"), for your shelves you will be fine using 18mm block-board and the front lipping only. Unless your daughter is storing dumbbells, then I would add the back lipping too(but even then I would doubt you need it). When you cut the block-board make sure the long grain in the core is orientated correctly.
When you look at kitchen units at 500mm with all the weight of the tins on they are fine, they are made from 15/18mm mfc with an iron on edge for a lipping, and they seem to take the weight just fine. You are using a much stronger material than mfc, so don't over build unless you have to, unless you want to of course

 

[Jacob]

... .....
My question therefore is should I put the lipping on the back as well as the front of the shelves?

Lipping (unless very big) no good. Blockboard no good for shelves. MDF worse. Solid wood best.

 

[Kalimna]

Jacob - out of interest, since it wasnt mentioned in your brief post, why is blockboard no good for shelves?

Adam

 

[mtt.tr]

Bloodboard works well for shelves

 

[woodbloke]

Bloodboard works well for shelves

Agreed, blockboard is to all intent and purposes 'solid' timber, especially if the core is lined up correctly. As usual, the words of wisdom spouted by a previous poster are in my view complete and utter tosh, so I'd disregard them...as I usually do :wink: - Rob

 

[Jacob]

It's just not as stiff as same thickness of solid wood in my experience - looking at a sagging shelf of paint tins as I type. Even if you get it going the right way.

PS a little fit of pique above, from the tosh master himself!

 

[bugbear]

... .....
My question therefore is should I put the lipping on the back as well as the front of the shelves?

Lipping (unless very big) no good. Blockboard no good for shelves. MDF worse. Solid wood best.

Verbs needed?

BugBear

 

[Harbo]

I made some shelves recently to fit into an alcove for my daughter.
300 wide 20mm sycamore spanning approximately 4', simply supported at the ends and the back. They have sagged quite badly at the front!
Was thinking of some lipping at the front to form a beam, but they are now planning to move. So that problem solved?
For supporting paint tins - old kitchen tops work well.

 

[Charlie Woody]

Thanks to everyone for their helpful suggestions. I have now decided that I will put lipping on the front of the shelves only.

The shelves will be supported on metal shelf supports to allow flexibility in spacing of the shelves. Do I need to drill the holes so that the lipping rests on the supports?

If I do then the back holes will need to be slightly higher to allow for the different thickness of the lipping (30mm) and the blockboard (18mm). Although the shelves will probably be pretty full, if my daughter decides to use any of them to display ornaments etc the difference in height of the holes might be visible!

What do you think guys?

 

[mtr1]

It's not usual to do that, I don't think it would add to the strength, and would look a bit odd IMHO.

 

[Charlie Woody]

Hi Mark

What I was thinking was that the load would be transferred via the lipping on the front to the shelf support. Am I incorrect in my thinking?

 

[mtr1]

Nope, I just don't see the advantage, on a 500mm wide shelf.