A Totteridge detached house usually has its chimney stack inside the building rather than in a wall shared with a neighbour, and it often serves four or more flues. That makes the breast wider and heavier than the semi-detached equivalent, so the support above is normally a beam on padstones designed by the structural engineer we appoint.
Wide internal stacks in N20 detached houses
Because these houses are detached, the stack tends to sit on an internal spine wall serving fireplaces front and back on two floors. That means more brickwork above whatever you remove than in a paired house, and it means the load lands in the middle of the plan where there is no external wall to take it. Gallows brackets suit a modest stack bolted into sound party wall masonry. On a wide internal Totteridge stack they usually will not do, and building control is far less willing to accept them since LABC withdrew its standard detail in 2024.
The practical answer is a beam spanning the width of the breast onto padstones cut into solid brickwork either side, sized for the retained masonry above rather than a rule of thumb. Where breasts are coming out on more than one floor we work top down, so nothing is hammered directly above a section that is only temporarily propped. Redundant flues are capped with ventilation top and bottom, because a sealed flue in an unheated void is how damp appears on a bedroom wall two winters later.
The roofline, the conservation area and building control
Chimneys are part of what the Totteridge Village conservation area is protecting. A tall brick stack with pots is a defining feature of the village roofline, so taking one off above the roof is an external alteration that Barnet's planning department will take a view on, and demolition in a conservation area can require conservation area consent. We flag this before design, because it changes the job: keeping the stack means supporting it permanently at loft or ceiling level, which is more steel, not less.
The structural work itself is signed off by Barnet Council building control under the Building Regulations. The engineer's design, the propping, the beam bearings and the flue capping are all inspected before anything is covered. Party wall notices, which dominate this job in a semi, are usually irrelevant on a detached Totteridge house because the stack sits within your own building. We still check the boundary position at survey, since a stack on a flank wall standing close to the next plot can bring the Party Wall etc. Act 1996 back into play, and it is far cheaper to establish before the scaffold goes up.
- Skirting, cornice and picture rail matched back in
- Building control notification and inspection sign-off
- Fireplace opening infill and new plasterboard finish
- Rubble bagged and carried out rather than dropped inside
- Ventilated caps and airbricks to disused flues
The GS Renovation Difference in Totteridge
On a wide internal Totteridge stack the difference between a proper beam and a bracket detail is the difference between a signed off job and a refused inspection. GS Renovation appoints the engineer, builds to the calculations, sequences the floors top down and manages Barnet building control. We also tell you early if keeping the stack above the roofline is the sensible conservation area answer.
- Flue capped with ventilation so the remaining stack stays dry
- Clean, tidy and reliable tradespeople
- A written scope and programme agreed before work starts
- Roof, flashing and leadwork made good where a stack comes down
- Rubble bagged and carried out, not tipped into the room below
- Our own trades on site rather than a chain of subcontractors