New window opening in cavity wall

[dorset972]

We are considering creating a new opening in a cavity wall and wish to avoid the use of temporary supports as the widow is on the first floor. Do we need to use needles etc as the opening will be a maximum of 700mm? We have created other internal openings using support but these were wider and mostly internal.
The property has only recently been built with 100mm brick 75mm cavity and 125mm lightweight block internally. We would like to avoid too much disturbance to the internal plasterwork. Also, is it best to just use a standard lintel or is anything else available for use in this situation?

 

[topbanana]

then cut out for your lintels first and place them and fix them in position b4 cutting out the rest of your opening .
concrete prestressed would be my option.
difficult to say without seeing but be sensible and careful.
you would need building reulatory approval for a new opening.

 

[dorset972]

Thanks for the above but cannot use p/s lintels as it is face brick on outside. Guess I'll just use a standard lintel and cut out a slot for it on the outer face and slide it in from inside. Shouldn't take too long with a decent grinder!

 

[topbanana]

guess you mean a catnic or similar!!
make sure you set it up so you dont have to disc brick but the slot between bricks.

 

[dorset972]

Yes, I've already got that sorted. No sense in making it more involved that it needs to be. Is the best form of support one strongboy on an acrow as this is what I've used in the past?