MEP design fee estimator

A benchmark construction cost per square metre for the building type is applied to the gross internal floor area to give an MEP construction value. A fee percentage is applied on a sliding scale by project value, then adjusted for region and specification level, and finally apportioned across the RIBA stages you select.

Because a precise figure produced from a floor area alone would imply a commitment that cannot be honoured before the drawings have been seen. The range reflects genuine pre-drawing uncertainty. An engineer normally confirms the fee within one working day of receiving the drawings.

GIFA is the total floor area of the building measured to the inside face of the external walls, including all storeys, circulation and plant space. It is measured in accordance with the RICS Code of Measuring Practice.

Yes. MEP design fees fall as a percentage as construction value rises, because the design effort does not scale linearly with size. The estimator applies that sliding scale automatically; the fee proposal issued after an engineer has seen the drawings sets it out in full.

Because roughly half the design work disappears and almost none of the overhead does. Mobilisation, the site survey, reading the architect’s information, coordinating with the other discipline’s designer — who on a split appointment is a third party rather than a colleague — checking and issue are all much the same whether one service is being designed or three. A single-discipline appointment is priced at around 60 per cent of the full MEP fee.

The building services engineer’s contribution to a BREEAM assessment: the evidence and modelling behind the energy, water and pollution credits, and liaison with the assessor. It does not include the licensed BREEAM Assessor, who is appointed separately and carries their own fee.

Both, under one scheme. New-build self-contained homes — houses, and flats in a block — are assessed under BREEAM UK New Construction: Residential, which is what the Home Quality Mark became when BRE brought it into the BREEAM range in April 2025. It scores each home individually and accounts for the shared areas, rather than assessing the block as a single non-domestic building. Buildings that house people without being self-contained homes — hotels, care homes, halls of residence, anything with shared living space or on-site support — stay under BREEAM Multi-residential in the non-domestic scheme. Selecting housing or flats in the estimator prices the residential scheme; the MEP contribution is the energy, water and ventilation evidence either way.

Because the two roles are not the same shape. Design effort concentrates in the early stages and drops sharply once the drawings are issued. The BREEAM role does not: Stage 5 is when material and equipment substitutions have to be checked against the credits that were claimed and the as-built evidence is assembled, which is where credits are most often lost. A construction-stage appointment therefore carries a larger share of the BREEAM fee than it does of the design fee.

No. A non-domestic Energy Performance Certificate has to be produced and lodged by an accredited assessor at Level 3, 4 or 5 depending on the services installed, so it is a cost passed through rather than design fee. The estimator shows it as its own line for that reason.

No. It is indicative only and is not a contractual offer. A fee proposal is issued after an engineer has reviewed the drawings and confirmed the scope, deliverables and programme.

Drawing upload is the next stage of this tool. In the meantime, send the general arrangement drawings to SDE and an engineer will normally take off the area and confirm a fee within one working day of receiving them.