Building work in Morden: area guide

This is our area guide to building work in Morden (SM4, Merton): the housing, the council rules that apply (Merton Council for planning) and every service we offer here. For whole-house refurbishment go to Home renovation in Morden.

Housing in Morden was built to a plan and it shows. The interwar expansion that produced the streets around Morden Park and the St Helier estate used a small number of standard house types repeated across a very large area, so we have almost certainly worked in your house's equivalent and can usually name the job. That helps with sequencing and knowing where surprises hide. It does not remove the need to design each job individually, because what previous owners did to these houses varies enormously even where the original drawings did not.

Count the homes in Morden and you get about 9,990: 17% built since 1945, 81% between the wars and 2% before 1919, with flats at 25% and houses at 75%. VOA Council Tax stock of properties, March 2025, for Morden Central, Lower Morden and St Helier North. Counts rounded by the VOA.

Standard house types, individual jobs: which wall carries what

The familiar SM4 brief is a rear extension, a reworked kitchen, a downstairs WC, a bathroom that no longer dates from the 1980s and a full rewire, often in one programme: a home renovation. Because the original plans repeat, the practical questions repeat with them: where the stair lands, which wall carries the first floor, how much of the rear wall can come out, and where the boiler and meters end up. Structure is still designed per house, because two apparently identical properties can have had entirely different alterations over the last forty years.

The construction itself is honest and workable: cavity walls, a hipped or gabled roof depending on the type, timber first floors and modest spans, which keeps beam sizes sensible when the ground floor is opened up as a load-bearing wall removal job. Where a house has been extended before, the join between old and new deserves close examination, because that is where insulation stops, damp proof courses fail to line up and roof coverings meet badly. We open those junctions up and put them right rather than building over them. Roof coverings on these types have generally had one replacement by now, so felt, battens and flashings are worth checking early.

Sewers under the garden come before the foundation design

On estate layouts of this period, public sewers frequently run through rear gardens rather than under the road, and a great many house extension jobs here sit over or beside one. Building over or within three metres of a public sewer requires a build over agreement from Thames Water, applied for before construction starts. It is a normal process rather than a refusal waiting to happen, but it takes time and can change the foundation design, so it belongs at the beginning of a project. A drainage asset search shows what is there before anything is drawn.

Where new work has to cross a sewer, the engineer usually designs the foundation to bridge it so no load is transferred onto the pipe, and existing manholes may need raising, relocating or replacing with a sealed cover of the correct type. None of that is unusual, and all of it is far less disruptive when known at design stage rather than discovered by a groundworker. We arrange the search, submit the application, and build to whatever the approved details require. The application also asks how surface and foul water will be handled around the new structure, so both designs are prepared together rather than one after the other.

Where to go next for work in Morden: house extensions in Morden, the Merton area guide, building work in Mitcham, building work in Wimbledon and Renovation Order of Works.