What size of doorway opening should be made?

[richard7761]

I'm cutting a doorway into a brick wall.

I notice that there is a half inch gap, top and sides, between the door frames in my house and brickwork. And a few shims inserted between the frame and brickwork.

I guess then that I ought to cut the doorway about half inch wider all around than the doorframe. Must be common practice I suppose.

 

[richard7761]

Is it the way to cut a doorway, make it half and inch wider than the doorframe? Just "yes" will do.

 

[Deleted member 174758]

Yes, so long as your cut-out sides are dead on plumb!

 

[tony1851]

It might be easier for you to make it a 1/2" gap all round (ie door frame 1" less wide than structural opening).
That way you can easily drive in wedges, and then squirt fill-and-fix foam in to secure it, then trim wedges after the foam has set. Don't mess around with screws and plugs and things.

 

[richard7761]

It might be easier for you to make it a 1/2" gap all round (ie door frame 1" less wide than structural opening).
That way you can easily drive in wedges, and then squirt fill-and-fix foam in to secure it, then trim wedges after the foam has set. Don't mess around with screws and plugs and things.

Thanks. I could see that there must be a reason why door openings are wider than the frame. I can see that it gives the builder some freedom in orientation. Just sort of wanted things confirming.

Hoping one 750mL can of Expanding Foam Filler will do two door frames. One 750mL can expands to about 37 litres. Probably enough.

 

[Deleted member 174758]

It might be easier for you to make it a 1/2" gap all round (ie door frame 1" less wide than structural opening).
That way you can easily drive in wedges, and then squirt fill-and-fix foam in to secure it, then trim wedges after the foam has set. Don't mess around with screws and plugs and things.

Ooh dear. I've seen quite e few young 'uns come unstuck that way........ Really dodgy house-bashers trick, that one - no place for that in my book. If you insert wedges into a frame, or probably more correctly for an interior doorway a casing, you stand a good chance of warping the jambs. Then add expanding foam without any form of anchoring and you'll definitely warp them (even more). The proper way to do it is to fix one jamb first loosely using something like #10 x 4in screws into brown plugs, plumb up, pack out then level the head and fix, pack plumb the other side checking that the distance across the opening is consistent all the way down. Onlt then can you use foam, and even that should be used sparingly. You might get away with that sort of thing on price work jobs with £30 MDF casings and a dopey foreman, on a decent quality job with £100 oak casings bow one and you'd pretty soon get your marching orders!

 

[tony1851]

It might be easier for you to make it a 1/2" gap all round (ie door frame 1" less wide than structural opening).
That way you can easily drive in wedges, and then squirt fill-and-fix foam in to secure it, then trim wedges after the foam has set. Don't mess around with screws and plugs and things.

Ooh dear. I've seen quite e few young 'uns come unstuck that way........ Really dodgy house-bashers trick, that one - no place for that in my book. If you insert wedges into a frame, or probably more correctly for an interior doorway a casing, you stand a good chance of warping the jambs. Then add expanding foam without any form of anchoring and you'll definitely warp them (even more). The proper way to do it is to fix one jamb first loosely using something like #10 x 4in screws into brown plugs, plumb up, pack out then level the head and fix, pack plumb the other side checking that the distance across the opening is consistent all the way down. Onlt then can you use foam, and even that should be used sparingly. You might get away with that sort of thing on price work jobs with £30 MDF casings and a dopey foreman, on a decent quality job with £100 oak casings bow one and you'd pretty soon get your marching orders!

We're in the 21st century now.

 

[Deleted member 174758]

It might be easier for you to make it a 1/2" gap all round (ie door frame 1" less wide than structural opening).
That way you can easily drive in wedges, and then squirt fill-and-fix foam in to secure it, then trim wedges after the foam has set. Don't mess around with screws and plugs and things.

Ooh dear. I've seen quite e few young 'uns come unstuck that way........ Really dodgy house-bashers trick, that one - no place for that in my book. If you insert wedges into a frame, or probably more correctly for an interior doorway a casing, you stand a good chance of warping the jambs. Then add expanding foam without any form of anchoring and you'll definitely warp them (even more). The proper way to do it is to fix one jamb first loosely using something like #10 x 4in screws into brown plugs, plumb up, pack out then level the head and fix, pack plumb the other side checking that the distance across the opening is consistent all the way down. Onlt then can you use foam, and even that should be used sparingly. You might get away with that sort of thing on price work jobs with £30 MDF casings and a dopey foreman, on a decent quality job with £100 oak casings bow one and you'd pretty soon get your marching orders!

We're in the 21st century now.

Yes, but a bodge job is still a bodge job

 

[tony1851]

You'll be telling him to drive in twist-cut-wedges and use 6" nails next!

 

[^woody^]

Just cut the damn opening the correct size of the lining. No packing, no messing

 

[tony1851]

Keep out of this!

 

[richard7761]

You know, an original door frame has 3 wedges on each side. Probably nailed in. Nothing on top. And there is no foam. But the plasterer just skimmed over the gaps between frame and door opening. Went in about 1/2 inch in the gaps.

 

[noseall]

We cut (internal) brick openings approximately 50mm bigger than the lining.

We then dab the sides of the opening with plasterboard trueing them up with a level.

I make sure that all the full bricks are marked on the wall prior to dabbing.

The dabbed plasterboard can be easily manipulated to create an exact opening size. Ideally about 810mm for a 30" wide door.

The casing is then fixed on the hinge side first, tight against the plasterboard and into my full bricks. The latch side is then packed (if necessary) and fixed the same.

Solid. No foam.

This method is great when fitting a standard depth casing in a cavity wall knock-through. It means you have a fully lined opening, a solid casing with all of the liner edges visible prior to skimming.