Door lintel help please

[Icky]

I'm considering breaking through the cavity breezeblock wall between my hall and my garage and fitting an external door between them ( an external door is required, I'm told ). This is one half of a project which also entails fitting an automatic garage door opener. Could anyone please tell me about the door lintel required? Would I need two lintels ( one each for the outer and inner cavity walls ) or do they come wide enough for both walls? Can I obtain something lighter than the concrete lintels I have seen up to now ( without sacrificing the strength required ) ? Can I fit the lintel by cutting a lintel sized horizontal 'slot' in the wall, securing the lintel into the slot, then cutting out the doorway below the lintel. Also, any tips would be appreciated about keeping everything ( like, the rest of my house ) in place while cutting this slot / doorway to stop a collapse before the lintel is in place and secure.

[BigWallop]

LOL

[Michael McNeil]

You need a fire door not an external door. Make sure it is 1 hour rated at least (but I'm not sure on that) and use intumescent strips in the frame and a door closer. It is a garage you are letting into your house. Somewhere that you store chemicals and put machinery loaded with petrol. So use draught excluders too.

Anything the wall is supporting will need proppng up. You can use accro's or just 3X2's or whatever, under a cross piece (both sides). You can use wood as a lintle too. It aught to be treated with preservative or be a timber that is impervious to whatever. It is not a good idea to use wood in a sealed wall though. Concrete is not that heavy. Are you sure you are up to the job?

You might want to seal a section of the house off with polythene to prevent dust. Keep doors and windows closed to stop through draughts etc. If you start in the garage you can carry your debris out that way.

[duncan]

and don't forget you will need building regs approval for this and it will need to be inspected and signed off by the local BCO (building control officer).

Not sure on the woodend lintel - the BCO if he's a nice chap, when he visits (before you start) should be able to tell you the type of lintel to use, although he may insist that you engage a structural engineer to assess the size of lintel.

duncan.

[John Armstrong]

Building regs only require a 30 minute fire door. The bottom of the door opening should be at least 100mm above the garage floor as well. See paragraph 9.14 of