New home integral garage doorway help

spudstoned

I have just exchanged contracts for my first home. It's a 3 year old build, and includes an integral garage which has no internal access doorway. I'm an blue collar mechanical engineer by trade, and keen to undertake a DIY project as a hobby. I'd like to install a doorway to the kitchen myself, to learn a few skills and have a sense of achievement. Very little experience with building but I am experienced with power tools and I have hung a door before. 

External garage walls are concrete block and brickwork with insulated cavity. The internal garage walls are 100mm concrete block (garage side) with 100mm stud walls (kitchen side). 

It's a non structural wall (joists run parallel and upstairs is stud wall only), but I will be fitting a lintel and using a precautionary strongboy to do so, the doorway obviously needs to be fire regulation compliant. I'll also be in touch with local authorities to check if I need the lintel and fire compliance checked over. 

I've got a few questions which I cannot for the life of me seem to find answers to online:

1. Would it be preferable to fit the door into the 100mm stud wall or 100mm concrete block opening? - I am supposing the concrete block would provide better security; I will be adding additional security to the up and over garage door anyhow, but the house will be empty for prolonged periods as I often work away - and I'd like any additional security I can get. Also, how is the door frame best attached to the blocks? Bolts through into the concrete blocks?
2. If I am fitting to the concrete block opening, how is best for "make good" of the 100mm stud wall void which will be opened up kitchen side? This would be too wide for a door jamb to fill, and the plasterboard behind the edges of the cutout will possibly be unsupported by studs. I'm really unsure on the typical way this would be approached. Expanding foam with drywall glued over it?
3. I'd want the door opening to be level with the current kitchen floor, which should leave approximately 150mm drop to the garage floor if built to typical new build standards. How is this best achieved accurately when the lintel is likely to be the first stab in installation? Would a "datum" hole normally be drilled through the complete wall section to measure from each wall-side, and then calculate lintel position based on door height and door frame thickness? I can't seem to find an answer to this. 

Apologies for the mass of text. This is all new to me, but I am really keen to see it through and have several weeks to plan/learn. I know I could get a builder to do this for around the £1k mark, which would pay for pretty much all the tools and supplies I'd need to aquire to do this myself. My time isn't a factor, as I'll enjoy doing it. 

markin

Stud walls can be structural, and you would need to frame a doorway in the stud wall to support the plasterboard and trim.   The actual door would go in the block work like any external door.

knightstyle

You need to check the regulations, it will probably need a fire door and surround.

FreeBear

markin said:Stud walls can be structural, and you would need to frame a doorway in the stud wall to support the plasterboard and trim.   The actual door would go in the block work like any external door.

Yup, bolt the door frame to the concrete block and then use timber to frame the rest of the opening. Being a garage, it will need to be fire rated. I used a steel door from a company by the name of Latham - 15 point locking with dead bolts. Good enough to satisfy my insurance company.

If you go for one of their doors, get it delivered before cutting holes in a wall - These are normally used as external doors, so are wider than internal domestic doors.

spudstoned

FreeBear said:

markin said:Stud walls can be structural, and you would need to frame a doorway in the stud wall to support the plasterboard and trim.   The actual door would go in the block work like any external door.

Yup, bolt the door frame to the concrete block and then use timber to frame the rest of the opening. Being a garage, it will need to be fire rated. I used a steel door from a company by the name of Latham - 15 point locking with dead bolts. Good enough to satisfy my insurance company.

If you go for one of their doors, get it delivered before cutting holes in a wall - These are normally used as external doors, so are wider than internal domestic doors.

I was gonna go with a 33"/838mm door over a standard internal 30"/762mm door. I'll be in and out the garage often and a few extra inches would be nice. 

Satisfying the insurance company was another thing I had read up on. I do like the idea of a steel door and Lathams have some nice non-fire rated steel doors; but I really wanted a paneled white fire door (which they don't seem to do as fd30, I'll have a look around). 

So the process should be like:
1. Make openings for strongboy at top of lintel position after establishing lintel position by drilling some reference holes through kitchen wall where door will sit (probably 4 holes at each exterior corner position of frame?). Fit strongboy. 
2. Lintel in blockwork w/ 150mm overhangs. Packed with slate and cemented in. Allow to dry before removing strongboy. 
3. Opening cut to suit fire door frame w/ 100mm+ drop to garage ground level.
4. FD30 frame fixed to blockwork with masonry fixings. Sealed with fire rated expanding foam.
5. Install FD30 door with FD30 fittings, door closer, and adequate security for insurance purposes. 
6. Frame out the hole in the stud wall opening with 100mm studs, plaster and make good. 

A couple of questions for step 6:
1. If stud wall has been cut to external frame dimensions, I will have to fit additional doorway support studwork "inside" the 100mm void? Can this be done without removing further plasterboard? I.e. can I slip the woodwork in behind the current opening edges, fix them in and screw current internal plasterboard to them? Would seem a lot easier than trying to remove more plasterboard and having to refinish the inside wall around the edges of the doorway. 
2. If the supporting woodwork is fit behind the current plasterboard void; and us flush to the doorway frame opening, could I just skim/plaster over the 100mm of woodwork or would I be best plasterboarding this 100mm section, using corner tape at the 90deg plasterboard edge etc. 

Seriously, thanks for the advice. Really really helped. 

marlot

A few observations from my (5 year old) house - they may point to regulations you need to follow?
There is a noticeable difference in floor levels - the garage is about 100mm lower than the house.
The door has a self closer on it
The ceiling is completely plastered - there are no gaps for flames or smoke to go to the room above.

FreeBear

spudstoned said: A couple of questions for step 6:
1. If stud wall has been cut to external frame dimensions, I will have to fit additional doorway support studwork "inside" the 100mm void? Can this be done without removing further plasterboard? I.e. can I slip the woodwork in behind the current opening edges, fix them in and screw current internal plasterboard to them? Would seem a lot easier than trying to remove more plasterboard and having to refinish the inside wall around the edges of the doorway. 
2. If the supporting woodwork is fit behind the current plasterboard void; and us flush to the doorway frame opening, could I just skim/plaster over the 100mm of woodwork or would I be best plasterboarding this 100mm section, using corner tape at the 90deg plasterboard edge etc.

Sod's law says where ever you cut the opening in the stud work, you'll end up with excessive unsupported plasterboard. Depending on the size of the existing stud work timber, you might be able to slot new timbers in through the cut-out, but the chances of being able to fix the new to old is going to be a crap shoot. Budget for taking plasterboard off to the next available stud either side and to the ceiling above. Give the OH the news that the kitchen can be redecorated once you are done.

I'd line the reveal with timber and plaster up to it then finish with architrave to match other doors in the house. Plastering the reveal, even with corner beads is asking for trouble. In time, you (or someone else) will drag something through, catch the corner, and put a ruddy great ding in it. Or it could be simple things like shopping or handbags knocking the corners each time you pass. Wood trim is much more durable & forgiving.

spudstoned

FreeBear said:

Sod's law says where ever you cut the opening in the stud work, you'll end up with excessive unsupported plasterboard. Depending on the size of the existing stud work timber, you might be able to slot new timbers in through the cut-out, but the chances of being able to fix the new to old is going to be a crap shoot. Budget for taking plasterboard off to the next available stud either side and to the ceiling above. Give the OH the news that the kitchen can be redecorated once you are done.

I'd line the reveal with timber and plaster up to it then finish with architrave to match other doors in the house. Plastering the reveal, even with corner beads is asking for trouble. In time, you (or someone else) will drag something through, catch the corner, and put a ruddy great ding in it. Or it could be simple things like shopping or handbags knocking the corners each time you pass. Wood trim is much more durable & forgiving.

Thanks FreeBear. I guess it will turn into experience with plasterboard and plastering then!

The door will be nearish to an external 90deg corner. I've read the first stud will be 400/600mm in from this corner. I guess I can place the doorway so that this stud will provide one of the opening edges to support the reveal timber? Then the opposing side I will frame myself. 

Last question! And I think I know the answer thanks to your advice. Would the whole opening be lined with the same timber? i.e. timber would be as wide as 100mm block, 100mm stud, 12.5mm plasterboard, 3mm for plaster/skim. So 215.5mm wide timber used to line the opening; then architrave the flush plasterboard to timber edges. In which case, when cutting the concrete block opening, and fixing the new doorway studs, I should account for the outer dimensions of the door frame PLUS the timber lining thickness? That all kinda make sense to me now!

Completely understand your statement about the disadvantages of a plastered doorway edge and will go with the timber architrave advice. 

Thankfully I have no OH to answer to when I start hacking down a perfectly fine new-build wall. I'd half thought about taking the complete wall down and having an open plan kitchen/garage, since they're my two favourite places. Not sure how I'll get a motorbike in the kitchen to pass fire regs though. 

Seriously, thank you for the advice. I really did try find these answers myself. Plenty of resources available online for a stud wall door opening, and a concrete block wall opening; but almost nothing for when a stud wall is attached directly to a concrete block wall. 

markin

You aim for 10mm larger than the door all around so you can adjust it level, and then just close the cavity with plasterboard i think.