How Our Basement Conversion Process Works — Step by Step
One of the most common concerns homeowners have before starting a basement conversion is not knowing what to expect — how disruptive it will be, how long it will take, and who is responsible for what at each stage. At Back To Basement Ltd we believe that a well-informed client is a happy client, so we have set out our entire process here, from the moment you first contact us to the day we hand over your completion certificate.
Every basement conversion we carry out in Leeds follows this tried and tested sequence, refined over 27 years and more than 100 projects. You will always know exactly where your project is and what is coming next.
STEP 1 Initial Contact & Free Site Visit
Every project starts with a conversation. Get in touch by phone on 07930 360 880, by email at info@backtobasement.co.uk, or through our contact form, and we will arrange a convenient time to visit your property.
During the site visit, Rubi will assess the space thoroughly — headroom, damp levels, foundation depth, access for materials, and structural condition — and talk through your ideas and requirements in detail. There is no charge for this visit and absolutely no obligation to proceed.
Following the visit, we will prepare a fully itemised, transparent quotation. We aim to get this to you promptly so you are not left waiting. The quote breaks down every element of the project clearly — no vague lump sums and no hidden costs. The price quoted is the price charged.
💡 Use our Project Cost Calculator on our website for an instant ballpark estimate before we visit.
STEP 2 Booking & Building Control Notification
Once you are happy with the quotation and ready to proceed, we take a £300 booking deposit to secure your place in our schedule. We will then agree a start date that works for you.
Before work begins on site, we contact Leeds City Council's Building Control department to notify them of the project and arrange a pre-work inspection visit. Building regulations approval is a legal requirement for all basement conversions — we manage this entire process on your behalf throughout the project. The building regulations fee of approximately £1,300 is paid directly by you to Leeds City Council.
💡 You do not need to deal with building control yourself at any point — we handle all communication and inspections on your behalf.
STEP 3 Strip Out & Excavation
This is where the physical work begins. Our team starts by stripping out any fixed items in the basement — stone shelving, ceiling surfaces, wall coverings, boards, and any redundant fittings. Any existing plumbing or electrical items are made safe and disconnected by our qualified tradespeople before removal.
We then break up any existing floor surfaces — whether concrete, stone, or other materials — and begin excavating the subfloor down to the desired finished floor level. This is often the noisiest and most disruptive phase of the project, but our team works efficiently to move through it as quickly as possible.
💡 You can continue to live in your home throughout the conversion in most cases. We keep the site as clean and contained as possible at all times.
STEP 4 Structural Works
Once the space is cleared and excavated, any necessary structural work is carried out. This may include removing walls, creating new openings, installing steel beams, or carrying out underpinning and foundation reinforcement work where required.
All structural work on our projects is designed and calculated by a qualified structural engineer who works alongside our team. Nothing structural is done without a proper engineering sign-off — this protects both your home and your building regulations approval.
💡 Underpinning is required on some older Leeds properties with shallow foundations. We will always tell you upfront if this is needed and what it involves.
STEP 5 Waterproofing & Drainage — Building Control Inspection
This is one of the most technically important stages of the entire project and the one we take most seriously. All walls are prepared and fitted with our cavity drain membrane system (Triton Platon) — a studded membrane that creates a drainage cavity between the wall and the finished surface, managing any water ingress and channelling it safely away.
A perimeter drainage channel is installed around the base of the walls, collecting any water that runs down behind the membrane and directing it to the sump pump, which automatically pumps it out and away from the property.
At this stage we also arrange for the Building Control inspector from Leeds City Council to visit and inspect the waterproofing installation before we proceed to the concrete pour. This inspection is a mandatory checkpoint — the inspector must approve the waterproofing before the floor can be laid.
💡 All our waterproofing is carried out to British Standard BS 8102 and backed by a Wykamol manufacturer's guarantee. We are Wykamol-approved contractors.
STEP 6 New Concrete Floor
Once the waterproofing has been inspected and approved, we pour the new concrete floor slab. The concrete sets and is ready to walk on within 48 hours, at which point we move straight on to the next stage.
On top of the concrete slab we install a layer of rigid insulation, followed by a cavity drain membrane, and then an 18mm chipboard floating floor. This creates a warm, dry floor system that sits above the slab and provides an excellent base for your finished flooring.
The chipboard floor is suitable for almost all finished floor types:
• Carpet
• LVT (Luxury Vinyl Tile)
• Laminate flooring
• Engineered hardwood
💡 For tiled finishes, a cement-based board or similar substrate should be applied over the chipboard before tiling to provide a waterproofed, stable base. We will advise you on this if tiling is planned.
STEP 7 First Fix Joinery, Plumbing & Electrics
With the floor complete, the first fix phase begins. This is where the internal structure of the basement takes shape.
Our team installs all stud walls, door frames, and internal partitions according to the agreed layout. At the same time our Gas Safe registered plumbers run all pipework for radiators, bathrooms, and utility areas, and our NAPIT accredited electricians install all wiring, consumer unit connections, and cable runs throughout the space.
Everything is installed before walls are boarded — this is the only chance to get services into the walls and ceiling correctly, so it is done methodically and thoroughly.
STEP 8 Drylining & Plastering
This is one of the most exciting stages for our clients — it is the point where the basement finally starts to look like a real room. Our team installs all plasterboard to walls and ceilings, creating the shape and definition of every space.
Once boarded, our experienced plasterers apply the finish plaster coat to all surfaces. We place enormous trust in our plasterers — a good plaster finish is something you only get one chance to do right, and it makes a significant difference to the quality of the final result.
💡 By the end of this stage, most clients are genuinely amazed at the transformation — the space looks completely unrecognisable from the damp cellar it started as.
STEP 9 Second Fix — Joinery, Electrics, Plumbing & Flooring
The second fix phase brings everything together. A large number of tasks are completed at this stage, working in a coordinated sequence:
• Second fix joinery — skirting boards, architrave, internal doors, and any bespoke storage solutions or fitted furniture
• Kitchen fitting — if a kitchen or utility area is included in the conversion
• Second fix electrics — all sockets, switches, light fittings, and any specialist installations such as underfloor heating controls or home cinema wiring
• Second fix plumbing — radiators, bathroom suites, utility room fittings, and any additional plumbing requirements
• Finished floor covering — we install all finished flooring types except carpets. For carpet fitting we can recommend a trusted local supplier
STEP 10 Final Touches, Sign Off & Handover
The final stage brings your basement conversion to completion. Decoration is the only element we do not carry out ourselves — we do not employ a decorator, but we are happy to recommend one if needed.
Once all works are complete and you are satisfied with the result, we collect the final balance payment and formally hand the space over to you.
You will receive:
• An electrical installation certificate from our NAPIT accredited electrician, which you submit to Building Control
• A visit from the Leeds City Council Building Control inspector for final sign-off — in our experience this always goes smoothly
• A Completion Certificate from Building Control, which is an important legal document you should keep safely — you will need it if you ever sell your property
• Your Triton waterproofing guarantee documentation
💡 The Completion Certificate is essential for future property sales. Keep it with your other important house documents.
What to Expect — A Summary
A typical basement conversion with Back To Basement Ltd takes between 8 and 14 weeks from start to completion, depending on the size and complexity of the project. Throughout every stage, Rubi is on site personally, and you will always be kept informed of progress and any decisions that need to be made.
We work across all areas of Leeds, including Headingley, Chapel Allerton, Roundhay, Alwoodley, Moortown, Meanwood, Horsforth, Calverley, Farsley, Pudsey, and all surrounding areas.
Ready to Get Started?
If you would like to discuss your basement conversion project with us, we would love to hear from you. We offer free, no-obligation site visits and fully itemised quotations across Leeds and West Yorkshire.
📞 Call: 07930 360 880
✉️ Email: info@backtobasement.co.uk
📋 Have a question first? Visit our FAQ page — answers to the most common questions about basement conversions in Leeds.
💰 Use our Project Cost Calculator for an instant estimate before we visit.