An architectural design studio in Northwest London and Hertfordshire. Extensions, lofts, conversions and new homes, surveyed, designed and taken through planning and building control in-house.
Free 2026 planning guides for homeowners and developersWe design extensions, lofts, conversions and small residential schemes across Northwest London and Hertfordshire, and run every project in-house from the first measured survey to the building control package.
Nothing gets lost between firms, and you always know who is responsible. The studio's background runs from large community projects to around 120 London homes, with training at Central Saint Martins (BA Hons Architecture) and London Metropolitan University (MArch, awarded with Merit).
Two free guides to planning and building, written from around 120 real London projects. Read yours before you speak to a designer, a builder or the council, and you'll start your project in the right place.
Whether you need planning permission, prior approval or a lawful development certificate, before you pay for drawings.
Build costs, professional fees and council charges set out plainly, so you can plan before you commit.
The ten mistakes we see most often, and the delays and refusals they cause.
Checklists to take to your designer, your builder and your neighbours.
For homeowners
Extensions, loft conversions and garden rooms, from the first idea to building control.
Read it before you speak to a designer, a builder or your neighbours.
For developers
Conversions, HMOs, commercial to residential and new build on small sites.
Read it before you make an offer. It's the cheapest due diligence you'll do.
Most home projects are won or lost on the route to approval. We work out yours first, whether that's permitted development, prior approval or a full application, and design to it.
Most small developments go wrong at the offer, not on site. We check the lawful use, the Article 4 directions and the space standards first, then take the scheme through planning and building control.
A clear process from start to finish. You always know what happens next.
Tell us about the property. You get a written quote and a free call about feasibility and planning risk.
One visit to survey the property accurately. Every drawing that follows is built on it.
We develop the design with you, then prepare, submit and manage the application to a decision.
Technical drawings, specifications and structural calculations, ready for your builder to price and build.
Four short questions, no account needed. We email your quote, usually within one working day.
Book a free 30-minute call. No hard sell, just honest answers about what's possible on your property or site.
Prefer email? info@denisesdesign.co.uk
Not always. Many rear extensions, lofts and outbuildings fall under permitted development, which is usually quicker and cheaper. It depends on the property type, its history and whether it's on designated land or under an Article 4 direction. We check this for every project and tell you which route we'd recommend.
It depends on the size of the project and how far you'd like us to take it, from the survey and planning drawings through to the building control package. Each stage is set out separately in your quote, so you can choose how far to go with us. Use the quick quote above and we'll email a tailored figure, usually within one working day.
Yes. Send us the address and what you're hoping to build. We'll check the lawful use, any Article 4 directions and the policies that apply, and tell you what's realistic before you make an offer.
We work across Northwest London and Hertfordshire. Lease plans and some survey work can be arranged further afield, so just ask.
Yes. We regularly pick up projects partway through, whether that's redrawing for planning after a refusal or producing the building control package from an approved design. Send us what you have and we'll quote for the remaining stages.
Your details are used only to answer your enquiry, prepare your quote or send the guide you asked for. We're registered with the ICO, we never sell or share your data for marketing, and if you don't become a client we delete your enquiry within 12 months. You can ask us to delete it sooner at any time. The full details are in our privacy notice.