Extra Deep Door Linings.

[paulandfrodo]

Hi,

I've got a few door ways that are quite deep. One example is :-

Room A

12.5mm Plasterboard
25mm Batten
25mm Celotex
225mm Brick
25mm Cavity
100mm Stud
25mm Celotex
12.5mm Plasterboard

Room B

NOTE: The build up is odd, as it's a complicated junction that's having to take into account some external walls that need insulating.

So, in total we are spanning through about 425mm. The door will open into Room A. As such, I would expect it to be hinged inside Room A.

I have two options (I think).

A. Line these doorways with some cosmetic sheet material that I can painted later to make it "look like" it's a solid deep timber door lining (perhaps 12mm ply). Screw a normal door liner to this and hang the door of the liner.

B. Line these doorways with something more substantial, so, perhaps Moisture Check MDF or Ply 18mm or 25mm, then hand the doors directly off these. Of course, I would treat the ends appropriately, so when I added the architrave the exposed edge (5mm) does not fur up.

We are basically trying to get the fancy effect you get in older houses, where you have really deep door linings in solid timber.

Please note, all the doors I will be fitting are reclaimed pine and in the size range of 900w by 2100 high, so I'm going to have to rip down and make door linings anyway. So, I'm not going to be able to use off-the-shelf stuff.

Thanks in Advance.

 

[Deleted member 174758]

Don't even attempt to build-up a plywood or MR-MDF lining that deep and hang a door directly off it - you will never make it work. The way deep liners are made is to build a frame or door casing with a rebated or grooved edge to carry extension pieces and fit that first.

Because there is very little to support your door lining I'd suggest that you make-up plain door linings without worked rebates but using housed joints. The housings are worked using a router and a home-made jig. The linings are glued and screwed together (note the horns - these are essential to assemble any door lining or casing):

One edge of the components (jambs and heads) must also be grooved (say 9mm wide x 12mm deep) with a router:

Make sure that you brace across the top corners of the linings to keep the heads square as well as bracing across the lower parts of the legs, say 100mm up from the bottom) to the jambs and the legs the same distance apart:

The bracings are something like 2x1 softwood battens and are pinned into place making sure that the pin holes will hidden by the architraves when they are fitted (so generally not within 10mm of the inside edges). The horns are sawn off just before installation (they add to stiffness whilst moving the lining to where it will be used), but the bracings are not removed until the lining has been fixed in place and foamed-in. Use a 6ft level to plumb-up the jambs and to ensure that they are not bowed and a 2ft level to level he head. You may well need to build-out from the existing wall with 3 x 2 or 2 x 2 softwood framing to get a fix into (using drilled and countersunk holes - these can be filled with glued pellets afterwards).

Once the foam has set the bracings can be removed. The linings are then built-out with rebate edged MR-MDF or plywood panels:

The rebated edge of the lining panels should be a couple of millimetres shorter than he depth of the grooves to ensure that you get a tight fit. You will need to cramp and glue these liners in place (a couple of 2 x 1 softwood clamps will do for each one)

The door lining will need to have door stops attached to it after the door has been hung. The liners can be made with recessed panels if you prefer that look

That's a start, so I hope that you can make sense of my scribblings

 

[Gerrydelasel]

There is an easier way. Make yourself a two non-rebated casings to start with using regular pine, like jobandknock's first image. Fit one at each 'end' of the doorway opening. Hang the door off whichever one you want.
Finally, add planted door stops made from 10mm MDF. Fix the MDF the full width across your two linings and you will have fully lined the whole of the doorway. (Sand the edges to prent furring up, as you described. Squirt some expanding foam behind the MDF if you want to avoid a hollow sound when knocking on it whist saying "ooh what a nice old deep door lining".)

 

[Deleted member 174758]

Personally I'm a bit dubious about installing two door linings in the way you suggest simply because there will in all probability be difficulties in getting them aligned properly without a lot of faffing about. Hence the "trade" way I described which I've come across on a number of jobs over the years. Incidentally we normally fix the extension linings either onto wedges knocked into the mortar joints and sawn off or onto battens/T-battens drilled and fixed to the underlying masonry. This is because with the best will in the world there is always the possibility that expanding foam will deform the sheet material used - and after it has been installed there is still the need to get a set of architraves on it in most cases (not easy if too much foam has been used).

 

[Gerrydelasel]

True, but since it is customary to build a casing outside the aperture first, with cross bracing to keep it square before putting it in, it wouldn't be hard to do the same with two casings -with bracing to keep them aligned before sliding into the opening. Just a thought.

 

[Deleted member 174758]

So basically you've never actually done this, then? In carpentry practical experience is sometimes a bit more useful than theory especially in an imperfect world

 

[Gerrydelasel]

I haven't done precisely that job, but that's how I would do it having done plenty of carpentry and from-scratch door casings before (it's a lot easier for me to line up a couple of rectangular frames than to cut 17 feet of rebates/grooves ). As a DIYer I look for simple solutions.

 

[Deleted member 174758]

For a start 17 feet of grooves and rebates would take under 30 minutes with a router and the appropriate cutters, maybe 1-1/2 hours with hand tools (rebate plane and plough plane) and would produce a better quality, more durable solution. To make your own casings it will probably be necessary to use a router and a largish straight cutter so the additional equipment I am talking about would be either a narrow straight cutter and a second side fence for the router or a bearing-guided groove cutter.

How much extra time willit take you to make a second casing? And how much more likely is it that there will be wind or bow in the legs of the second lining which will make the installation more problematic. The approach I proffer is effectively "textbook" and has been proven to work over generations. I've installed frame and panel versions of it on site on quite a few occasions s well as making-up simpler versions on site.

"In the end no one will remember how long it took, only how well you did it." Precisely

 

[Gerrydelasel]

I've installed frame and panel versions of it on site on quite a few occasions as well as making-up simpler versions on site.

Good for you. The OP is of course free to do whatever he likes, so our bickering is redundant.