GS Renovation carries out structural alterations throughout Harrow, across the interwar semis of HA2 and HA5 and the period and suburban houses around Harrow on the Hill and Stanmore. Over 30 years we have formed new openings, replaced tired joists, underpinned settling foundations and installed supported openings that keep these solid 1930s homes standing true.
New openings and joist repairs in Harrow homes
The interwar houses on Harrow's generous plots lend themselves to structural change: a wider opening between kitchen and dining room, a doorway punched through a solid brick wall, or a new steel to carry a first-floor extension. Each begins with a structural engineer specifying the beam and its padstone bearings, followed by temporary propping and a controlled, staged cut so the masonry above is never left unsupported.
Replacement joists are a common request in Harrow's 1930s stock, where original timbers can sag, split or suffer from historic damp near bathrooms and flat-roof additions. We fit new joists to the engineer's schedule, tie them into the load-bearing walls and, where a room is being opened up, coordinate the joist work with the steel beam so the floor above stays level and quiet underfoot.
Underpinning and supported openings in Harrow
Some Harrow houses show movement, whether from the shrinkable London clay under parts of the borough or from mature trees on these leafy suburban plots. Where an engineer confirms subsidence, we underpin in a carefully sequenced hit-and-miss pattern of bays, extending the foundation down to firmer ground so the structure is stabilised before any cosmetic repair is even considered.
All of this falls under the Building Regulations rather than planning, so Harrow Council's building control inspects the underpinning bays, the new openings and the beam bearings as work proceeds. Where an opening, a bearing or an underpinning bay touches the party wall shared with your attached neighbour, the Party Wall Act applies and you serve the notice first. Only external work in a conservation area needs separate planning consent.
- Basement and cellar alterations with retaining support
- Temporary works, propping and needling
- Reinstatement, plastering and finishing after structural works
- Steel goalpost and portal frames to the engineer's design
- Load paths carried down to foundations on new piers and pads
Why Harrow Homeowners Choose GS Renovation
For structural alterations in Harrow, GS Renovation gives you a single accountable team from survey to certificate. We commission the engineer, handle party wall notices on shared semi walls, arrange Harrow building control inspections and carry out underpinning, new openings and joist work with proper propping. Tidy, methodical and backed by 30+ years across the borough's interwar homes.
- Dust screens and floor protection in occupied homes
- Underpinning carried out in sequenced bays, never one long trench
- Rated 4.9 from 31 reviews on MyBuilder
- Registered in England, Companies House no. 14611254
- Existing structure protected and monitored as the engineer requires
- Temporary works and needling planned before demolition starts