Mill Hill sits on London Clay, and clay moves with the seasons. GS Renovation carries out structural alterations across NW7, forming supported openings, replacing failed joists and underpinning where an engineer confirms movement. We appoint the engineer, build to the calculations and put the work through Barnet Council's building control, backed by more than 30 years of hands on experience.
What London Clay does to a Mill Hill house
London Clay shrinks as it dries and swells as it wets, and the movement is seasonal. In a Mill Hill house the classic sign is a diagonal crack that is wide at the top and tapers as it runs down, often at a corner or beside the bay, opening through a dry late summer and closing again over winter. Shallow interwar foundations feel that more than deeper modern ones do. A crack you can post a coin into, or one that is visibly wider this year than last, is a job for a structural engineer before it is a job for a builder.
Trees matter more here than most owners realise. A mature oak, poplar or willow near the house draws water out of clay through the summer and the ground around its roots shrinks. Remove that tree and the opposite happens: the clay slowly recovers moisture and lifts, which is heave, and it can carry on for years afterwards. So we do not fell first and think later on the streets backing onto Arrandene Open Space. The engineer decides whether the tree stays, and in the conservation area you must notify Barnet before touching it.
Openings, underpinning and sign off across NW7
For a new opening we work to the engineer's beam and padstone design, prop off sole plates, cut in stages and never leave load unsupported overnight. Where joists have sagged, or wet rot has taken an end bearing out, we replace to the correct span and grade rather than screwing something thin alongside and calling it a repair. Underpinning follows the engineer's sequence, with short bays dug and concreted in a set order so the wall above is never undermined. Barnet Council's building control inspects the excavations and the bearings before they are covered.
Two other consents catch people out. Excavating within three metres of a neighbour's building, to a depth below their foundations, is notifiable under the Party Wall etc. Act 1996 even where your Mill Hill house is detached and shares no wall with anyone. We flag that early, prepare the notice and set out the timing, and you serve it as building owner. In Mill Hill Village, demolition and any work to a listed building also needs consent from Barnet's planning side, which runs entirely separately from building control.
- Reinstatement, plastering and finishing after structural works
- Floor structure, joist and beam replacement
- Bressummer and bay window support to period frontages
- Crack repair, helical bar stitching and masonry restraint
- New door and window openings in solid masonry
Why Choose GS Renovation in Mill Hill
Homeowners in NW7 come to us because we treat clay ground honestly. If the answer is that you need a structural engineer, or a period of monitoring before anyone digs, we say so. When the design arrives we build to it exactly, sequence the underpinning bays properly, and get Barnet Council's building control to inspect before anything is covered. More than 30 years of hands on experience stands behind that.
- One point of contact on the phone, not a call centre
- We build to the party wall award the surveyors agree, to the letter
- Itemised pricing, so you can see what every stage costs
- Building control inspected at foundation, steel and completion
- Clean, tidy and reliable tradespeople
- Building control applications and inspections coordinated for you