We would like to open up the light well to the front of our semi detached late Victorian terrace house.
The house is a typical Victorian layout, with a bay going from the top all the way down through the basement and onto the footings. We are planning to convert the basement space into a large habitable space, of which we have had structural calculations and planning already approved - details attached.
Unfortunately, structural calculations were not included for the front light well as this was a late addition.
You can get all of the dimensions from the attached drawings, but the proposed lightwell is not as detailed in the plans. We propose to build a 1400mm deep lightwell x 1400mm wide, spanning the middle window of the bay.
I would like details on how the retaining walls of this light well should be formed. With the pavement running alongside the existing front wall of the front garden, there is a possible surcharge that needs to be considered.
We have considered both a brick gravity wall stepped back into the retained soil, or a rebar with mesh in the concrete base of the lightwell and horizontal and vertical bars, hollow block work and concrete filled. The concern with the latter approach is the effect of the toe of the slab putting extra pressure on the existing wall of the house (9 inch brick), as well as the side walls of the light well acting like buttresses also adding force.
What we are looking for is the most cost effective way of achieving this, although we are happy to over engineer if it means we can get the design back sooner.
Work needs to be completed within the next 48 hours, preferably sooner.