Sagging drawer unit made from MDF

[Callum Red]

Hi,

Around 2 years ago I had a carpenter build two sets of drawers built into the alcove around my chimney breast. I didn't really know anything about woodworking at the time, so I didn't challenge any of his build. The initial quality looked really good and fitted into the space well. Skip to present day and we've now got quite a bit of sag going on (Somewhere around 7-11mm!) to the point where the bottom of the small drawers have started rubbing on the top of the drawers below.

The larger unit was built from c 3/4" MDF, with three large drawers at the bottom, and four smaller (in two rows) above. Internal width is 41" / 1045mm and depth is 14" / 355mm. It has no front or rear support, only the side mount. The second unit, although narrower by a few inches, has the same structure and problem.

Having looked at 'The Sagulator' and other threads, it's clear MDF wasn't the right material for this build. The unladen drawers themselves are all made from 3/4" too and have a decent amount of weight to them + whatever is on top.

I find myself with some time on my hands now and was looking to fix this problem.

My thoughts were either:

A: Move inside rails up to adjust for sag. This would fix the problem now, but not if they continue to droop.
B: To push the sagging areas upwards and support into where they should be with batton screwed full width into rear wall or
C: Push & Support with London Brackets - 3 on the 'middle' section and one inside each of the top.

Clearance between the rear of drawers and wall is c 20-25mm.

Wanted to see any suggestions or recommendations before I started the job!

Pictures:
Frontage; Frontage close up showing sag; drawers removed to show 'carcass'.

TIA!

CRed

 

[Racers]

Is there space at the back of the draws to add brackets or blocks at the back under the top and bottom in the middle to support it.

Pete

 

[doctor Bob]

The horizontal internal shelf needs lifting. I'd get a bit of clean angle iron 20 x 20mm and screw it across the sag to lift it.
Take all the drawers out, and use a jack to lift that middle shelf, put a good base under it so the bottom doesn't give way, once you have it flat, put a brace at the back and fix th angle iron.
The shelf should have have a good solid lip on it in the first place to stop the gradual sag.

 

[Callum Red]

The small drawers back directly to the wall, with about 25mm of clearance.
There is a sheet of MDF backing the draws and the bottom but does nothing for the support so happy to cut some away.

I had a London Shelving Bracket in the shed and having tested it out, looks like there's clearance to put those in without interfering with the movement of drawers.

 

[Joshjosh]

I would also go about the way doctor Bob is suggesting.
Have you tried contacting the carpenter who fit it? I know if it was my job I would want a client to let me know so I could fix it
Cheers Josh

 

[Mike Jordan]

The real cause of this problem is the incompetent clown who claimed to be a woodworker. It's a very rare customer who has the sense to even ask about qualifications! We have all seen the transit van with a dozen trades written on the side, the guy inside has probably watched a YouTube video or two but usually has no provable qualifications. It's the customers job to be suspicious! Two young men of my aquaintance set themselves up as tree surgeons, the advert in yellow pages read brilliantly but neither of the clowns had even had a chainsaw safety course in truth. They climbed a few trees but the business fortunately folded before they killed anyone.

 

[dzj]

Yeah, it's a mess.
You could put the smaller drawers down on the plinth. This way you would have direct support for the
mid-vertical member. Maybe an angle iron or some such to straighten the top.

 

[woodbloke66]

The horizontal internal shelf needs lifting. I'd get a bit of clean angle iron 20 x 20mm and screw it across the sag to lift it.
Take all the drawers out, and use a jack to lift that middle shelf, put a good base under it so the bottom doesn't give way, once you have it flat, put a brace at the back and fix th angle iron.
The shelf should have have a good solid lip on it in the first place to stop the gradual sag.

Really the only way to sort this one out. MDF is appalling stuff for weight bearing applications and will bend even under it's own weight which is why it needs to be stored carefully - Rob

 

[AndyT]

Given that MDF was the wrong material, I'm a bit surprised that nobody has suggested replacing the undertop and middle board with some proper wood. Ideally something stiff like oak. (I read on here that B&Q now sell oak boards. I've not queued up for hours to look at any, but they might be an available source for something good enough for a new interior.)
The painted external top could be retained.

The challenges will be to get some firm fixing onto what is there but I expect a combination of battens and steel brackets could do it.

 

[Doug71]

Looks like the carpenter didn't make a bad job apart from choice of material. I would call him back to have a look, he might appreciate the chance to put it right and realise the error of his ways, he might still be making the same mistake 2 years on!
As said get the top and shelf straightened up and fixed back to wall, in theory the middle panel should then support the front edge but a bit of angle iron attached to the front would definitely help.

 

[thetyreman]

I wonder if the 'carpenter' sealed the MDF properly? looks like he's painted the outside but not inside, which is a bad idea with solid wood as well, always seal both sides equally. That may be another reason why it's ended up like this. To be honest this is something I'd just rip out in anger if I had this, no way I could look at a sag like that and stay sane

 

[woodbloke66]

I wonder if the 'carpenter' sealed the MDF properly? looks like he's painted the outside but not inside, which is a bad idea with solid wood as well, always seal both sides equally. That may be another reason why it's ended up like this. To be honest this is something I'd just rip out in anger if I had this, no way I could look at a sag like that and stay sane

I'd be inclined to agree with you; a saggy bookshelf would drive me potty :lol: - Rob

 

[peter-harrison]

The centre divider between the upper drawers is already a bracket. It has way more strength than you need. The problem is that it isn’t fixed to the wall. If you jack it up as suggested earlier- maybe a bit too high- and then fix it securely to the wall, it should be fine. You will need to make sure it’s well packed so as not to cause more distortion by pulling it too close to the wall.
Btw I agree that your craftsman was anything but!

 

[NicoWilson]

Difficult to see from the photos but is the central section or the shelf tied to the wall?

 

[Max Power]

A length of angle iron screwed to the centre partition and to the wall would sort it, once you manage to get it back in line. It will need to be a reasonable size though, so that the screws don't end up too close to the back edge and pull away

 

[Callum Red]

Hello! Realised I never shared my solution.

I jacked the bookcase from within to slightly above resting flat. I then drilled four London brackets into the wall to support the additional weight.
Once the jack was let off, they sat squarely against the brackets and true to straight/flat.

Thanks for the help internet wood folk!

 

[AndyT]

Thanks for coming back with the answer - it's always nice to hear that something has worked.

 

[sammy.se]

thanks for the update. Closure is nice (especially for cabinet makers).