Cricklewood roofs come in two families and they convert differently for structural reasons as much as planning ones. The Edwardian terraces have cut roofs with purlins that can usually be reframed around. The interwar semis are often hipped and may have trussed or partly trussed roofs, which changes both what is possible and what it costs to open the space up.
Usually, but the price depends on the roof structure as much as the design. Check whether the roof is a traditional cut roof with purlins and struts, which can be reframed, or a prefabricated trussed roof, where a full replacement structure has to be designed and installed before the trusses come out. On the interwar semis a hip-to-gable with a rear dormer gives the most volume; on the Edwardian terraces an L-shaped dormer over the closet wing does.
Planning at a glance
Cricklewood
Planning at a glance in Cricklewood
Local planning authority
Brent
Likely approval route
Householder planning application or permitted development, depending on conservation status, listing and property type — confirmed for the exact address before drawings begin
Statutory determination time
8 weeks for most householder applications (13 weeks for major applications)
Where most projects start
Planning Route Review — £395 inc. VAT, credited in full against your package if you proceed. Find my package →
The roof structure is the first thing worth establishing, because it changes both the design and the cost. An Edwardian terrace generally has a cut roof: rafters, purlins and struts assembled on site, with the load carried down through internal walls. That structure can usually be reframed to open up the space, with new steel or engineered timber taking the purlin loads so the struts can come out. Many interwar houses were also built with cut roofs, but some later ones — and most postwar additions — use prefabricated trusses, where the diagonal webs occupy the entire roof void and cannot simply be cut away. Converting a trussed roof means designing a replacement structure before anything is removed, which is entirely feasible but is a different job with a different price.
Hip-to-gable is the highest-value move on the interwar semis. Building the sloping hipped end up into a vertical gable extends the ridge and converts a dead sloping corner into full-height space, and with a rear dormer it usually produces a proper double bedroom and an ensuite. The new gable wall has to be carried on adequate support and the loads traced down to foundations designed for a lighter roof, which on the clay soils common to these streets is worth checking rather than assuming.
On the Edwardian terraces the equivalent move is the L-shaped dormer, wrapping from the main rear slope around onto the closet-wing roof to produce a double bedroom with a shower room over the wing. The valley junction where the two roof planes meet is the technical heart of it and has to be formed so it drains reliably. The dormer cheek usually sits on or near the party wall, which brings the Party Wall etc. Act 1996 into the programme.
Head height gates both. About 2.2 metres of clear height under the ridge before conversion is the working minimum, because the new floor and ceiling build-ups take roughly 300 millimetres between them. The interwar semis usually clear it; the Edwardian terraces are more variable, particularly where a first-floor ceiling has been lowered. Fire safety then shapes the internal layout, because adding a habitable storey makes the house three-storey under Part B and generally requires a protected escape route from the top floor to a final exit.
Local analysis
What matters in Cricklewood
Cut roof or trussed roof: what it means for your loft
This distinction is worth understanding before you get quotes, because it explains why two apparently similar houses on the same street can produce very different prices. A traditional cut roof is assembled from individual rafters, purlins and struts, and the void beneath it is largely open. Converting it means providing an alternative structural path — usually steel beams or engineered timber at purlin level, and a new floor structure spanning between load-bearing walls rather than sitting on the existing ceiling joists, which were never sized for habitable loading. That is standard work. A prefabricated trussed roof is different: the trusses are engineered as complete triangulated frames, the diagonal webs run right through the space, and cutting any member without replacing its function compromises the whole roof. Converting one means designing a full replacement structure — typically steel or a new cut roof — installing it in a sequence that keeps the roof supported throughout, and then removing the trusses. It is entirely achievable and thousands of such conversions are done, but it is more structure, more temporary works and more cost, and any quote that does not acknowledge it has not looked properly. We identify the roof type at survey and tell you which project you are buying before fees are committed.
Hip-to-gable on a street of matched pairs
The interwar semis around Cricklewood were built in pairs and frequently in long runs of near-identical pairs, and a hip-to-gable has to be designed with that in mind. A semi-detached pair reads as a single symmetrical composition from the road, and squaring off your hip while the neighbour keeps theirs is visible in a way the floor plan does not convey. Outside a designated area, Class B permitted development may allow it within the volume limits, and many of these streets already carry examples that establish the local pattern. Inside a designation it needs a householder application and the symmetry becomes a live consideration that has to be answered in the elevation. The options worth testing before submitting are a partial hip-to-gable that retains part of the original slope, a rear dormer alone with rooflights to the front, or a scheme that holds the ridge line and takes its volume from the dormer. Where the neighbouring house has already been converted, matching it is usually the strongest argument available. We draw the street elevation with the proposal in it, because that is the drawing the decision actually turns on.
Thinking about a project in Cricklewood?
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Roof additions fall under Schedule 2, Part 1, Class B of the General Permitted Development Order, allowing an enlargement within a volume allowance, set back from the eaves and finished in materials of similar appearance. The allowance is larger for a semi-detached house than a terrace.
Class B is removed on designated land. Brent covers all of its residential conservation areas with Article 4 directions, Barnet has ten conservation areas covered by or with such directions, and Camden operates its own. Since all three boroughs fall within 1,400 metres of the checked point, jurisdiction is established before designation.
Rooflights fitted close to the plane of the roof fall under Class C and remain available on many houses where a dormer does not. Flats hold no householder rights, and in a subdivided house the roof space is often retained by the freeholder rather than demised to the top-floor flat.
On a run of matched interwar semis the hipped roofline gives the street a consistent silhouette, so a hip-to-gable that squares off one end leaves the pair visibly unbalanced. Within a designated area that asymmetry is the objection most often raised, and it is an elevation argument rather than a floor-plan one.
Front roof slopes carry the designation wherever one applies. Dormers facing the street are resisted and front rooflights are controlled, while rear slopes, read mainly from private gardens, are treated with more latitude across all three boroughs.
The designations near Cricklewood are Mapesbury and its extension, Brondesbury and its extension, Dudden Hill, Willesden Green and Willesden extension under Brent, and Railway Terraces under Barnet. Each has its own boundary and its own administering authority.
Do I need planning permission for a loft conversion in Cricklewood?
It depends on designation and on which borough covers the address. Class B permitted development can cover a rear dormer and a hip-to-gable within volume limits, with a larger allowance for a semi than a terrace, but Class B is removed on designated land. Brent, Barnet and Camden each maintain their own conservation boundaries and Article 4 directions, so jurisdiction is confirmed before the designation check.
How do I tell if my roof is trussed?
Look in the loft: a trussed roof has diagonal timber webs forming triangles right through the space, so the void is criss-crossed and hard to move through. A traditional cut roof has rafters and one or two horizontal purlins supported by angled struts, leaving a more open volume. The difference matters because converting a trussed roof means designing and installing a replacement structure before the trusses come out, which costs more.
Can a trussed roof still be converted?
Yes, and it is done routinely, but it is a bigger structural job. The trusses are engineered as complete frames, so their function has to be replaced — usually with steel or a new cut roof — installed in a sequence that keeps the roof supported throughout, before the trusses are removed. Any quotation that does not acknowledge the roof type has not looked properly, so it is worth establishing at survey stage.
What is hip-to-gable and will it suit my semi?
It means building the sloping hipped end of the roof up into a vertical gable, extending the ridge and turning a dead sloping corner into full-height space. It suits the interwar semis around Cricklewood and, combined with a rear dormer, usually produces a proper double bedroom with an ensuite. The new gable needs adequate structural support and the loads traced down to the foundations, which on clay soils is worth checking rather than assuming.
How much head height does my loft need?
Around 2.2 metres of clear height under the ridge before conversion, because the new floor and ceiling build-ups take roughly 300 millimetres between them. The interwar semis generally clear it comfortably; the Edwardian terraces are more variable, particularly where a first-floor ceiling has already been lowered. A measured survey gives the figure for your roof, and a neighbour’s success is not evidence about yours.
Will a hip-to-gable be refused because it breaks the pair’s symmetry?
It can be a live consideration on designated land, because a semi-detached pair reads as one symmetrical composition from the street. Where the neighbouring house has already been converted, matching it is usually the strongest argument. Where it has not, a partial hip-to-gable retaining part of the slope, or a scheme that keeps the ridge and takes its volume from the rear dormer, is often the better application. The street elevation is the decisive drawing.
Do I need fire doors after a loft conversion?
Almost always. Adding a habitable storey makes a two-storey house three-storey under Part B, which generally requires a protected escape route from the top floor to a final exit: an enclosed stair, fire doors to habitable rooms opening onto it and mains-linked alarms. Where the ground floor has been opened up, restoring separation at the foot of the stair is usually needed. Sprinklers are an alternative in some layouts.
What does a loft conversion architect in Cricklewood cost?
We publish fixed-fee packages rather than a percentage quoted before anyone has seen the roof, starting with a route review credited against the design work if you go ahead. The stages are feasibility and consent strategy, then planning or certificate drawings, then building regulations and tender information. Structural engineering, party wall surveyors, application fees and building control charges are separate and identified at the outset.
Discuss a loft conversion in Cricklewood
Send your Cricklewood address, photographs of the roof from outside and, if you can, a photograph from inside the loft showing the structure. We will tell you whether the roof is cut or trussed, what that means for the scheme and the cost, which council decides it, and what the fixed-fee next stage involves.
