How Thick for a Door Frame

[andrewm]

It's been a while since I did any serious butchering of wood but I have a door frame to build for a set of internal doors. 3m or so wide with two side panels and two opening doors in the centre.

I was going to use 135mm deep timber all around but am now worried that this may look too deep from the 'inside'

I am therefore wondering if I could get away with using 95mm (nominal 2x4) instead. This should be OK for the head and jambs because they will be secured to the wall but I am a little worried about the requirements for the mullions. What does the team think? This will be constructed from hardwood (don't know the species, it's whatever the builders merchant has so nothing exotic. A fine grained deep red colour).

As a supplementary question: what would be the best way to attach the sidelights to the frame?

 

[andrewm]

Another picture. This is the cross-sections of the various verticals. The question is though can I get away with making them smaller without compromising any structural integrity?

 

[Spectric]

I think interior doors are 30mm thick & exterior ones 40mm. The door lining is the width of the wall it sits in.

 

[MARK.B.]

Top and bottom would imho look better perhaps 100mm for the top and 135mm on the bottom

Edit . Are we talking about the doors or just the frame ?

Edited it again Ignore this post ,just reread your post , it's been one of those days

 

[Doug71]

Will it have any kind of cill/bottom on the frame to help tie it all together?

 

[scooby]

As Doug said, a cill would help but (imo) it would look better without one. Annoyingly, I did the exact same job on a house near me about 13 years ago and can't remember how I secured the jambs (that the doors were hinged on) to the floor.

I do recall, on the one I did, the 2 outer panels were narrower and had a middle rail (with glass above and a timber panel below) so the door jambs were pretty twist resistant to start off with. I'm 90% certain it didn't have a cill.

As for dimensions, left and right would be fine (in my experience). I'd be tempted to beef up the two inner jambs a bit, even if its just to allow some longer screws for the hinges. I wouldn't make them smaller.

Edit: I've just recalled a bit of the work I did. I'm pretty sure (on mine) the 2 doors were relatively narrow (2ft sounds about right) and the panels were probably a bit narrower. So the overall thing was narrower than your 3m requirements, and I didn't once think the frame looked chunky.

 

[Jacob]

Your "mullions" have to bear the weight of the doors and look a bit lightweight I think. I'd go for 12/40/12 perhaps, which would leave you with 64mm thickness on the closed side - but you could relieve that with a 12mm half round on the other edge of the planted door stop.
It'd be good to have the doors opening flat against the side panels as far as possible. You wouldn't want a cill for an internal door, but a cill could be useful for the fixed side panels and help with the overall structure.
The side panels would fit same as for the doors but without a clearance gap. The join would be visible but could be lost with a bead (3/8" ?) along the edge of the door stiles.
PS or you could have thinner stiles on the panels setting them back from the door "mullions", with a shadow line.
PPS forgot to say - the 135 looks fine to me! You need a bit of substance or the whole frame could feel wobbly when you open/close the doors

 

[andrewm]

Thanks all.

No cill, the floor is flush between two rooms.

The doors are standard Premdor pattern 10 with glass and I already have those. They are 35mm thick.

This is an ex-outside wall so 300mm thick or so, so the frame is not the full depth.

I'll stick with 135mm deep but may not have enough overall width to take the mullions to a full 12/40/12 as suggested by Jacob. Overall width is 3150mm plus a bit for padding out of square walls. The side panels are fixed so screws could go all the way through the mullions into the adjacent frame if necessary. I could probably take them to 25 or even 30mm if I reduce the width of the side pieces which will be attached to the wall. Any thicker than that and I will have to think about taking something off either side of the door (3mm off either side of each door would allow a 40mm mullion). At that thickness it might be easier to laminate from several thinner pieces rather than cutting out of a single section. The frame will be painted so don't see that being a problem aesthetically.

I was planning on securing the bottom of the mullions into the floor below. There is 22mm walnut boards and then concrete below in that section.

 

[RobinBHM]

20mm is a bit thin for door hinge screws.

I would screw the sidelights in place through the glass rebate.

 

[andrewm]

20mm is a bit thin for door hinge screws.

I would screw the sidelights in place through the glass rebate.

The hinges can be screwed through the mullion into the adjacent sidelight.

Sidelights will be screwed to the frame but any suggestions as to the best way and where to screw appreciated.

 

[Jar944]

If I remember correctly, I put about 6 equally spaces screws per jamb leg and mullion on this door

 

[andrewm]

Nice doors. Thanks for sharing. Fortunately my design is a lot simpler - to go with the more modern style of the house.