SAP calculations in Redbridge

The volume of work in Redbridge

Redbridge decided 991 householder applications in its latest published year, granting 82.8 per cent and deciding 94.7 per cent in time. It also dealt with 812 lawful development certificates.

66.2 per cent of households live in a house, and 57.1 per cent are owner-occupied. A semi-detached house averaged £681,463 in the latest Land Registry figures. Households with room to extend are common, and so are permitted development schemes.

Permitted development is not an energy exemption

Many Redbridge owners use permitted development and a certificate for a loft or a rear extension. That settles the planning position. It does not settle the energy position, because a building control application still follows. The limits for new elements are: New elements in existing dwellings, limiting U-values W/(m²·K): roof 0.15, wall 0.18, floor 0.18, windows 1.4 (or WER Band B), doors 1.4.

The glazing rule is separate: Windows, roof windows, rooflights and doors in an extension should not exceed 25% of the extension floor area plus the area of openings removed or covered. If a design cannot meet it, the alternative route applies: Alternative routes: area-weighted U-value (para 10.9) or a SAP calculation against a notional extension (para 10.10).

Our lawful development certificate service in Redbridge deals with the planning side, and the energy information follows from the same measured drawings. That matters because a loft or rear extension built under a certificate still needs a completion certificate, and the energy evidence sits in that file. Gathering it afterwards, from a finished building, is the slow and awkward way round.

Larger extensions and the Green Belt

Redbridge granted 46 larger home extension prior approvals and refused 93 in the latest year. That is a considerable number of both, and it shows owners use the route often. Whether it works depends on the neighbours and the site. We read the refusals as well as the grants, because the reasons given tell us which designs the council is wary of, and we draw the next one to avoid them.

34 per cent of the borough is covered by Green Belt polygons. Inside it, the size of an extension is controlled by policy before energy becomes the question. There are also 16 conservation areas and 134 list entries to check.

The standard changes with the date you deposit

For new homes the method is: For new dwellings AD L 2026 names two methods: the Home Energy Model (HEM) and SAP; validity dates are in the Notice of Approval. The change-over reads: AD L 2026 takes effect 24 Mar 2027 (24 Sep 2027 for higher-risk building work). The transitional note says: AD L/F 2021 continue where plans/notices are deposited before 24 Mar 2027 and work starts before 24 Mar 2028.

We read your deposit and start dates against those lines before we fix a quote, because it changes which standard your calculation must meet. If a delay in design or a late change to the plans would move you across the line, we say so, and we suggest the order of work that keeps the earlier standard open where the rules allow it. That conversation is free, and it takes place before you pay for any calculation. The building regulations drawings in Redbridge are then drawn to match.

Related pages

For the whole borough see architectural drawings in Redbridge. For the same service nearby, try SAP calculations in Newham and SAP calculations in Waltham Forest.