Custom MDF door frame

CrazyFool · 30 May 2019

Hey guys

I've done all the door frames in my house and am now down to to my last one. It's going to be a double door in a rectangle arch between 2 lounges.

It's an odd size (so will need custom doors too)
Height 237cm
Width 181cm

I understand I'll have to make a custom door lining for this, I conveniently have a load of surplus MDF. Will this do?

I know MDF linings can carry a normal door but just not sure about double doors of this size.

Thankfully, the arch walls are perfectly plum so I'm less worried about the MDF bowing as I can just fasten it to the wall with many screws.

I just want plain slab doors so I was thinking of gluing together 2 x 18mm MDF sheets and cutting to size.

What do you guys think?

Thanks in advance

CF

Gerrydelasel · 13 Jun 2019

CrazyFool said:
I know MDF linings can carry a normal door but just not sure about double doors of this size.

You're still just hanging one normal-sized door on normal hinges. It doesn't matter that there's two of them.

I just want plain slab doors so I was thinking of gluing together 2 x 18mm MDF sheets and cutting to size.

Hmm that sounds extremely heavy to me. I'd be tempted to make it hollow.

CrazyFool · 13 Jun 2019

Gerrydelasel said:
You're still just hanging one normal-sized door on normal hinges. It doesn't matter that there's two of them.

Hmm that sounds extremely heavy to me. I'd be tempted to make it hollow.

Thanks for the reply mate.

I hadn't thought about weight.

If I stick 2 x 18mm doors together the finished door will probably weight 60-65kg.
If I stick 2 x 15mm doors together the finished door will probably weight 50-55kg.

Is this too heavy?
I've seen fire doors weigh 42kg.

Aren't screws rated at 100kg each or something like that?

Thanks again

CF

Gerrydelasel · 13 Jun 2019

Aren't screws rated at 100kg each or something like that?

I'd be more concerned with the screws simply pulling out of the MDF rather than failing. But by my calcs the solid MDF door would be around 50kg (?) so I'd have thought a hollow one would be fine.

Notch7 · 13 Jun 2019

Not worth the hastle.

I bought a 44mm fire door blank from Howdens not long ago, it was only about £35 from memory.

CrazyFool · 13 Jun 2019

Notch7 said:
Not worth the hastle.

I bought a 44mm fire door blank from Howdens not long ago, it was only about £35 from memory.

Thanks buddy
Was that for an 8 foot door? It is quiet a tall opening as above.

I tried calling howdens but dont have a trade account.
My google search tells me I'm paying upwards of 100 quid for an 8 foot fire door.
Any other suggestions to save me having to make a door out of MDF?

Cheers
CF

foxhole · 13 Jun 2019

I used 25mm mdf on a custom door frame [300mm wide], holds a door fine.My doors are ledger and braced, thickest one is made from scaffold boards with T hinges..

Notch7 · 13 Jun 2019

CrazyFool said:
Thanks buddy
Was that for an 8 foot door? It is quiet a tall opening as above.

I tried calling howdens but dont have a trade account.
My google search tells me I'm paying upwards of 100 quid for an 8 foot fire door.
Any other suggestions to save me having to make a door out of MDF?

Cheers
CF

Ah sorry, I didnt spot the height.

Off the shelf you would need an 8 x 4 fire door blank -yeah about £100

Have you any thinner mdf sheets -you could make a torsion box door with some softwood battens

I wouldnt recommend gluing 2 sheets of 18mm mdf -the screws in the hinges will struggle to hold the weight.

CrazyFool · 13 Jun 2019

foxhole said:
I used 25mm mdf on a custom door frame [300mm wide], holds a door fine.My doors are ledger and braced, thickest one is made from scaffold boards with T hinges..

Notch7 said:
Ah sorry, I didnt spot the height.

Off the shelf you would need an 8 x 4 fire door blank -yeah about £100

Have you any thinner mdf sheets -you could make a torsion box door with some softwood battens

I wouldnt recommend gluing 2 sheets of 18mm mdf -the screws in the hinges will struggle to hold the weight.

Thanks for the replys fellas.
I just googled torsion box doors. Looks like a fun project.

What thickness MDF do you recommend and what thickness battens do I need in between?

The width of the doorframe is 150mm

Thanks in advance

phatboy · 13 Jun 2019

CrazyFool said:
What thickness MDF do you recommend and what thickness battens do I need in between?

If you see most standard hollow doors, the facings are about 2mm thick! 4mm MDF each side would make a sturdy door, with wood glue on everywhere wood makes contact. Then make the timber between up to whatever you want your finished door to be. 30mm would seem about right, and I think it's a size B&Q sell ready planed to?

Mr Chibs · 14 Jun 2019

Just give a bit of thought to getting nice flat sheets... usually when I see thin mdf/ply they are warped to buggery, if you do the torsion door, you may need lots of weights to keep the sheet flat, whilst the glue sets, good luck.

Gerrydelasel · 14 Jun 2019

I think 4mm is too thin -you'll feel it flex if you happen to push it where a void is. I'd go with 10mm or thereabouts. I also prefer my doors thick, like 38mm.

CrazyFool · 14 Jun 2019

Thanks for the replys fellas

I was thinking 10mm face too.

What final door thickness do you recommend if its a 150mm wide door frame?

Also, is there any last hope for a thinner solid MDF door?
According to my calculations, I can get the finished door weight down to ~47kg if I stick two 15mm MDF sheets together.
That's not too far away from a standard 42kg fire door although 30mm is on the thin side.
I'm thinking of sacking the whole MDF door jamb idea and just getting some good timber, which will probably accept the hinge screws better as well.

The reason being is that I'll need some sort of lip for both doors to meet in the middle. 2 MDF sheets stuck together would be perfect as you could just offset one to give you a natural lip without needing to route a lip out.

I can see a lip being very complicated to make with a torsion box door.

Besides I can swear the door at town hall weighs about 100 kilos lol. How do they manage to support such a heavy door there?

Thanks for all the help thus far.

Mr Chibs · 15 Jun 2019

With three good hinges, I wouldn't have thought you'd have much of a problem with the weights you mention.

I've had some cottage oak veneered doors from Howdens and they are really heavy, just under 40Kg, they are a pain to manhandle into place when fitting, but are really solid once on. 3 ball bearing stainless hinges and you're done. One frame I had to make was 180mm wide, only thing I would say is if you are adding door stops afterwards, make the wood wider than standard 'door stop' gubbins from wickes.
If you have a rebated frame you won't have to worry about this.

CrazyFool · 15 Jun 2019

Mr Chibs said:
With three good hinges, I wouldn't have thought you'd have much of a problem with the weights you mention.

I've had some cottage oak veneered doors from Howdens and they are really heavy, just under 40Kg, they are a pain to manhandle into place when fitting, but are really solid once on. 3 ball bearing stainless hinges and you're done. One frame I had to make was 180mm wide, only thing I would say is if you are adding door stops afterwards, make the wood wider than standard 'door stop' gubbins from wickes.
If you have a rebated frame you won't have to worry about this.

Thanks for the advice chief.
Thinking of going for these:
https://www.screwfix.com/p/smith-lo...nt-hinges-fire-rated-102-x-102mm-2-pack/7594j

Not sure if they're ball bearing but they've been tested to handle 120kg.
If they are indeed rated at 120kg I'm inclined to glue 2x18mm MDF sheets (~60kg) for a thicker sturdier feel. Not sure what you guys think about that?

I'll be going for Parliament hinges because I want the doors to open out 180 degrees against the wall.

I'll be going to the timber yard to pick up some 150mm x 18mm lengths for the jambs/header.
I'll be sure to pick up thicker door stoppers.

I've read that the jambs should be securely attached to the walls with longer screws as jamb failure is more common than screw/hinge failure.

I'll be grateful for Any further advice.

Cheers

diynot

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Custom MDF door frame

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