Extensions, new buildsand refurbishmentsacross Hertfordshire

Green Belt across the southern belt

Three Rivers, Hertsmere and large parts of St Albans and Dacorum sit in Metropolitan Green Belt. Extensions there are tested against whether they are disproportionate to the original dwelling, and replacement dwellings are tested against whether they are materially larger than what they replace. Owners who bought a house that has already been extended twice frequently find there is little or no allowance left.

We calculate original volume and cumulative additions before designing, and where the allowance is used up we look at internal reconfiguration, loft space or a replacement dwelling strategy instead of a doomed application.

• Original-dwelling volume evidenced before any design work
• Replacement dwelling tests assessed where relevant
• Honest advice at the free visit when the arithmetic will not work

Timber frame, lime and listed fabric

St Albans, Hertford, Berkhamsted, Hitchin and the surrounding villages hold a large stock of genuinely old buildings, including timber-framed properties. These need lime plasters and mortars, breathable build-ups and careful structural intervention. Cement render, gypsum plaster and impermeable insulation applied to a historic wall trap moisture and cause decay in the frame: a common and expensive error.

We specify to the fabric, not to habit, and where listed building consent is required it is prepared as part of the application. Our Grade II listed project in Notting Hill was delivered on the same principle.

Chalk, clay and variable ground

Hertfordshire's geology shifts from London Clay in the south to chalk further north, with clay-with-flints in between. Clay areas bring seasonal shrinkage and heave, particularly near mature trees; chalk areas bring the possibility of solution features and dissolution hollows, which can require deeper or redesigned foundations.

We arrange the structural input at design stage so foundation design responds to the actual ground rather than a standard assumption, and so the cost sits in the contract sum instead of arriving as a variation.

• Ground conditions established before the price is fixed
• Tree proximity and clay movement factored into foundation depth
• Structural design coordinated with the architecture from the start

Access, conservation streets and neighbour impact

Market-town centres in St Albans, Berkhamsted, Hertford and Hitchin have narrow streets, limited parking and restricted delivery access, while village lanes can rule out large vehicles entirely. These constraints affect programme and cost, and in conservation areas they come alongside controls on scaffolding, skips and materials storage.

We assess access before pricing, so the programme reflects how materials will actually reach the site. On constrained streets that single piece of planning is often the difference between a project running to time and a project stalling.