MDF storage unit /entertainment unit

[WhoMe?]

Hi

What thickness of MDF do people recommend for a storage unit. It will be self supporting off the floor and fit onto a end wall measuring 3m x 2.4m. The base unit including the circulation space behind will be about 600mm deep, the cupboards and shelves etc. above will be set back and total about 500mm deep.

The layout that I'm planning will have 6nr verticals including the end panels and a back panel. They'll be full width horizontals along the bottom of the base unit (raised off the floor), the top of the base unit for the TV shelf etc. and to the top and bottom of a high full width cabinet (away from the ceiling with a front bank panel to ceiling).

So far I've been told 25mm

Would you build this as one unit or in say 3 parts? I'm never planning on moving it.

Thanks

 

[foxhole]

18mm is ideal , build as many units as you design dictates , easy to install in smaller sections. remember if you build full height units you can’t do that on the floor as you won’t have room to lift them into position.

 

[Deleted member 174758]

What thickness of MDF do people recommend for a storage unit. It will be self supporting off the floor and fit onto a end wall measuring 3m x 2.4m. The base unit including the circulation space behind will be about 600mm deep, the cupboards and shelves etc. above will be set back and total about 500mm deep...

...So far I've been told 25mm

One can only presume by people who have never had to manhandle furniture of that thickness. If making something yourself 18mm is generally taken to be a reasonable thickness unless the item in question can be delivered in semi-knocked-down form (e.g. a bookcase carcase where the shelves are loose and sit atop Tonk strips). Below 15mm MDF becomes difficult to joint (basically there isn't enough strength in it). The other consideration is joint strength - if you screw items together there is a limit to the weight that screws will carry - in thicker materials you need to start looking at using loose tenons (e.g. Dominos) or multiple hardwood dowels, etc instead of screws which then requires the use of glues and clamps to assemble the structure - so the method of construction also influences the type and density of material you choose. 18mm Medite MDF weighs in at 34kg per sheet (8 x 4ft/2330 x 1220mm) or approximately 11.4kg/square metre, veneered MDF in the same size is generally nearer to 45 or 50kg per sheet (15.1 to 16.8kg/m2), MR-MDF (Medite) at 18mm is 42kg/sheet (14.1kg/m2). Knowing those figures may help you understand what you are dealing with in terms of getting the item into place

The layout that I'm planning will have 6nr verticals including the end panels and a back panel. They'll be full width horizontals along the bottom of the base unit (raised off the floor), the top of the base unit for the TV shelf etc. and to the top and bottom of a high full width cabinet (away from the ceiling with a front bank panel to ceiling).

Sorry, but if you try to make that in one piece it will potentially disintegrate when you try to move it. I used to make larger bar backs and c ash desks than that at one time, but they were invariably double-thickness of MDF with laminate over the joints to get the required rigidity, and it would often take 6, 8 or more men to lift them off the floor and load them into a lorry for delivery (FLTRs tend to damage stuff). It is far better to build modular units and fix them together lioke kitchen units as @foxhole recommends. To that I'd add a bar fitting trick - build a softwood ladder frame out of something like 2 x 2in (44 x 44mm) or 3 x 2on (70 x 44mm) pAR softwood and sit your cabinets on top of that. That gives you a single solid base, which can easily be levelled (if your floor is out of level or hollow or crowned) and makes connecting the units together far easier than trying to pull them together atop carpets. Bear in mind that units like this will need to be assembled on the floor and lifted up into position, so you need to make them a little shorter than the ceiling height of the room in order to lift them upright

Before starting this, maybe get a free copy of Sketchup and use it try to see what your units will look like.

 

[WhoMe?]

Thanks for all the good advice, the ladder frame definitely makes sense as the floor is uneven. I was going to use adjustable legs under the cabinet but the frame sounds a lot easier. What should the spacing of the noggins (I think) be, every 6"?

I'll definitely build it in units

How should I support the bridge of cabinets that go over the TV space as I can't fixed it to the wall behind? Just to the backboard I'll incorporate?

18mm it is!

 

[Deleted member 174758]

What width, height and depth of unit overall are you looking at? What size of TV are you considering (width x height)? A ladder frame for an 1800mm wide x 500mm deep unit made from 3 x 2in PSE pine would look something like this (assuming 25mm overhangs at either end and the front, you may need to do further work in designing the rear so as to be able to scribe around skirtings, etc):

The bearers are at 400mm centres coming in from each end. They would be better placed beneath the upright end panels of the individual units where they could carry the weight better.

Supporting the flying bridge is another issue. In part it depends on the weight of the bridge and what load it is intended to carry. Personally, I'd consider another 3 x 2in PSE or 2 x 2in PSE ladder frame fixed (bolted, dowelled or at least screwed) to the upright cupboards at either side:

The frame can be boxed in MDF too to hide it:

These are just rough and ready images to illustrate the principles

What sort of design features are you considering? What finish are you considering? What experience of woodworking do you have? What sort of tool kit do you have? (and what are you prepared to buy?) Do you have anywhere to work on this project? What is your budget? These are the sort of questions you need to be answering.

 

[WhoMe?]

Thanks for the very thorough answer

What size of TV are you considerin

Not sure but I'd like to future proof up to may 46"

What width, height and depth of unit overall are you looking at?

It's about 3m wide by 2.4m high, 600mm deep

rear so as to be able to scribe

It needs to be away from the back wall as the wall is REALLY uneven with an odd bump, due to a previous owners attempt to block up a removed chimney breast.

Supporting the flying bridge is another issue. In part it depends on the weight of the bridge and what load it is intended to carry. Personally, I'd consider another 3 x 2in PSE or 2 x 2in PSE ladder frame fixed (bolted, dowelled or at least screwed) to the upright cupboards at either side:

Nothing major, books.and general stuff. Your solution makes sense

What sort of design features are you considering? What finish are you considering? What experience of woodworking do you have? What sort of tool kit do you have? (and what are you prepared to buy?) Do you have anywhere to work on this project? What is your budget? These are the sort of questions you need to be answering.

No special features and a painted finish. I have friends in building trade and one who is an ex contractor chippy. I'll buy the cheaper tools that I'll use again and borrow the expensive ones. I might order boards cut to size or get a friend round to cut.

If it dry, the garden is near for cutting. There's a fairly large area in front of where it'll be installed where I can assemble. Budget is what's needed, within reason. I won't cut corners on costs in order to do what's best, but won't go mad either.

Theses were all probably rhetorical questions but I've previously given them all a think.

Thanks

 

[Deleted member 174758]

Yes, a lot of questions which were kind of rhetorical, but with good purpose, I'm sure you'll agree. Making up a unit is little different from building kitchen cabinets (and I'd suggest inspecting your upper cabinets for construction methods), after all, cabinetmaking is simply fancy box making.

In terms of weight and strength 18mm MDF is pretty good, although you might want to consider 12mm for the backs as a weight saver. The backcan n be grooved-in, rebated in (my preference) or simply screwed on, but fitted snugly they do provide a lot of the rigidity that a big cabinet needs. The neatest way to assemble units is dowels, biscuits or Dominos - all of which make for a fairly rigid carcass, but they all require specialist tools and cramps to assemble. Simpler is screw and glue, but it isn't as strong. Just don't be tempted by pocket hole screws which were designed for plywood and don't work well with MDF or chipboard in my experience. Whichever way you go you'll need a flat surface to work on for assembly - a sheet of 18mm chipboard placed on a relatively flat, firm surface can provide this. Without it you will struggle

Good luck with the build