What the price covers
Take out a wall, and something else must carry what it carried. Our calculations, from £435, work out what: for each beam, lintel, padstone and changed foundation, the loads, the size of the member and the bearing. The sizes are marked on your drawings, so the builder works from a single set.
We add a temporary-works note on the order of propping and removal, so the opening is made in a safe sequence.
The rules a calculation answers to
The reference is Approved Document A, the 2004 edition with its 2004, 2010 and 2013 amendments. Its simple rules for wall thickness cover residential buildings of up to three storeys, and a floor supported by a wall may span no more than six metres centre to centre of bearing by the simple route.
Beyond those limits, or where steel is involved, a calculation replaces the tables. For a house of up to four storeys the building is consequence class 1 for disproportionate collapse, a classification that sets how much robustness the design needs.
When the neighbour comes into it
Structure and party walls overlap. A new foundation or a basement dig close to an adjoining building may need an excavation notice at least a month before work: within three metres and deeper than the neighbour's foundations, or within six where the excavation cuts a 45 degree line from them. Cutting into a party wall or fitting steel into it needs two months' notice.
We flag these when we run the calculations, and prepare the notices from £55 per neighbour.
Competence and approval
Whoever designs building work must have the skills, knowledge and experience for the job. That is the reason for a calculation by someone who does this work, and not a guess by a builder with a tape.
Building control has five weeks to decide a full plans application, unless a longer period is agreed, and the calculations are part of it. See our structural calculations page for what is issued.
How to order
Send your drawings, or let us draw them. Tell us which walls, floors or roofs change and we confirm the fee.
The figures, with sources
Doc A
Approved Document A, the 2004 edition with the 2004, 2010 and 2013 amendments.
Source: GOV.UK, Structure: Approved Document A, checked 15 Oct 2026
3 storeys
Tallest residential building the simple wall-thickness rules in section 2C cover.
Source: Approved Document A, section 2C, checked 15 Oct 2026
6 m
Longest span of a floor carried on a wall under the simple rules, centre to centre of bearing.
Source: Approved Document A, paragraph 2C23, checked 15 Oct 2026
Class 1
Consequence class for a house of up to four storeys, for disproportionate collapse.
Source: Approved Document A, section 5, Table 11, checked 15 Oct 2026
3 m / 6 m
Distances from a neighbouring building within which digging can call for an excavation notice.
Source: Party Wall etc. Act 1996, section 6, checked 15 Oct 2026
Reg. 11F
A person designing building work has to be competent at it, in skills, knowledge and experience.
Source: Building Regulations 2010, regulation 11F, checked 15 Oct 2026
5 weeks
Period for building control to decide a full plans application, unless longer is agreed in writing.
Source: Building Regulations 2010, regulation 14A, checked 15 Oct 2026
Questions
Do I need calculations to remove a wall?
If it carries load, yes. We check what the wall carries and tell you whether a calculation is required.
Do you inspect the work?
Our service is the calculation and its issue. Inspection during the build is by building control; we can advise on what to show them.
Can you calculate from another designer's drawings?
Yes, once we have read them and confirmed the fee.
What if the design changes?
We update the calculation at no charge until the plans are approved.
The fee for structural calculations
What you get
- A calculation for every beam, lintel and foundation changed
- Sizes and positions marked on your drawings
- A temporary-works note for the builder
- The calculation package for building control
- Revisions free until the plans are approved
