# Sell basement conversion and underpinning leads. Yes. AceLeads buys basement conversion enquiries from independent lead generators across the UK, and most of the demand sits in London and the South East. The lead has to say which job it actually is: a tank and convert inside an existing cellar, a floor lowering, or a full dig-out under the house with underpinning. Send it with the scope, the property and the consent trail attached, we accept or reject it within 48 hours, and you are paid a fixed fee for every accepted lead. The biggest domestic ticket on the board, and the one vertical where the same two words cover two different jobs. A cellar tanked and converted and an excavation under the footprint are an order of magnitude apart, so an enquiry that does not say which it is gets priced as the smaller one. ## What we accept - The owner’s name, a working UK phone number and a deliverable email address. We check both before a fee is due. - Confirmation that they own the property, and whether they hold the freehold. A leaseholder who has not mentioned the freeholder is the most common failure point in this vertical. - Which job it is, in the owner’s own words: converting an existing cellar, lowering the floor, or excavating new space under the house. - What is under the property today, and the existing head height if there is a cellar. A tape measure figure is ideal, “I can stand up in it” is workable, a blank is not. - An approximate floor area of the space they want, and whether it extends beyond the current footprint. - Property type and age, and whether it is terraced, semi-detached or detached. Neighbours either side change the party wall position entirely. - What the space is for: living space, a gym, a cinema room, an annexe or a self-contained flat. - Whether a structural engineer or a party wall surveyor is already appointed, and whether notices have been served on adjoining owners. - How far planning or a basement impact assessment has got, where the borough asks for one. - The full postcode and a timescale. Specialists on this brief work boroughs, not regions. - Consent evidence with every submission: the form URL, the exact wording shown, the IP address, the user agent and the timestamp. ## Who buys these leads The buyers on this brief are basement conversion specialists, underpinning and structural contractors, waterproofing and tanking firms and high-end design-and-build companies, most of them working a tight travel radius around London and the South East. ## What we reject Almost everything we turn down here fails for one of two reasons: the enquiry never separates a membrane job from an excavation, or the person asking cannot authorise a dig under their own house. Every rejection carries a code from a published, closed list, you get it within 48 hours and you can appeal it. A rejected lead stays yours and we make no claim on it. ## Rejection reasons in full - **A basement enquiry that never says which job it is** - Nothing on what is under the house today, no head height, and no word on whether the floor has to come down or the space has to go beyond the footprint. A tank and convert and a full dig-out with underpinning arrive as the same lead when nobody asks, and the cheaper reading is the one that sets the price. Three questions on your form move most of these from rejected to qualified. - **Damp, tanking and cellar repairs with no conversion behind them** - A leaking cellar, a failed membrane, a sump pump that needs replacing, mould in a space nobody intends to live in, or an insurance job after a flood. These are real jobs and a damp specialist wants them, but they are remedial waterproofing rather than a conversion, so they fail on category however complete the record is. - **Anyone who cannot authorise a dig under the property** - Tenants, leaseholders in a converted house with no freeholder consent mentioned, owners of a flat above a shared basement or vaults, and anyone whose neighbour owns the ground in question. Excavation and underpinning need the person who can serve party wall notices in their own name. Enthusiasm from someone who has to ask permission first is not a project yet. - **Storage, boarding out and “could I use my cellar”** - Owners asking whether the cellar could be cleared, boarded, lit or dry-lined for storage, bikes or a wine rack. No habitable intent, no waterproofing design, no structural work, and no budget in the bracket a specialist quotes at. It is a genuine enquiry for a general builder and it has no buyer on this brief. - **Trade, tender and feasibility enquiries** - A main contractor sourcing an underpinning subcontractor, an architect gathering budget costs for a client you cannot name or contact, a surveyor collecting comparables, an owner researching whether a basement would add resale value, and pre-purchase enquiries on a house nobody has completed on. Intent has to sit with the person who owns the property and is spending the money. - **Recycled, co-registered or incentivised enquiries** - A duplicate of an enquiry already submitted, by you or by another affiliate, inside the dedupe window on our lead standards page. Also enquiries round the comparison sites several times over, prize draw and free-gift entries, and consent wording that mentions only “trusted partners” without naming us or clearly describing who will make contact. Screening runs on normalised phone and email, and a consent trail that does not match the enquiry fails on its own. ## What moves the fee on a basement lead Two tiers are open on this vertical: a raw lead that clears the acceptance standards, and a qualified lead that also carries the scope detail named in this brief. Both figures are published on the rate card and nowhere else, they are indicative, and postcode and volume move them. The gap between the two tiers is wider here than almost anywhere else we buy, for the obvious reason: on this trade, scope is most of the value. ## What moves a lead up a tier - **Which job it actually is** - Converting an existing cellar, lowering the floor, or excavating new space under the footprint, and whether underpinning is expected. This one field separates two projects that sit an order of magnitude apart, and it is the first thing a specialist looks for. Capture it in the owner’s own words rather than as a tick box they will guess at. - **Head height and floor area together** - The height under the house today and the rough area the owner wants are what confirm the scope, and they are what let us route the lead to a waterproofing firm or to a structural contractor. One without the other leaves a qualifying call for somebody else to make, and that is the difference between the two tiers. - **Party wall and structural progress** - A named structural engineer, a party wall surveyor appointed, notices served on adjoining owners, or a basement impact assessment underway. These are the strongest buying signals in this vertical, because an owner already paying professional fees is funded and moving rather than daydreaming about a gym. - **A full postcode, not a region** - Most of this work happens in London and the South East, buyers there quote by borough, and what a borough asks for in a basement impact assessment changes from one to the next. A full postcode gets a decision in hours. “London” on its own is held rather than paid, and holding is nobody’s idea of a good outcome. ## Payment terms - **Decision** - Within 48 hours of submission - **First payment** - Within 14 days of your first accepted lead - **After that** - Every Friday, for everything accepted up to the previous Sunday - **Payment method** - Bank transfer (BACS). We raise the self-billed invoice, so there is nothing to chase. - **Clawback** - Once we accept a lead it is ours. We never claw back an accepted lead because a buyer did not convert it. We reverse a payment only for proven fraud, a proven duplicate, or a consent failure. ## Requirements that apply to every lead - Capture pages must meet UK GDPR and PECR standards. Specific, informed, freely given consent, a real privacy notice, no pre-ticked or bundled permissions, and AceLeads or a clearly described category of recipient named at the point of capture. Consent evidence travels with every lead: timestamp, IP, page URL and the exact wording shown. Capture pages are audited before the first lead is accepted. - Every lead is verified before it counts. Contact details are checked, duplicates are caught across all affiliates rather than just your own, and known junk patterns are filtered automatically. Leads that fail verification are rejected with a named reason and are not paid for. ## Frequently asked questions ### What counts as a basement conversion lead? A property owner turning space below ground into habitable rooms: a tank and convert inside an existing cellar, a floor lowering to win head height, or a dig-out under the footprint with underpinning. Damp and tanking repairs on a cellar nobody is converting, boarding a cellar out for storage, and garage or outbuilding conversions above ground all sit outside it, and they are the three things most often submitted here by mistake. ### How do I tell a cellar conversion from a dig-out on my form? Three questions do most of the work. Is there a cellar under the house today, can you stand up in it comfortably, and does the space you want go beyond the footprint of the house. An owner who has a cellar, can stand in it and wants the same footprint is usually a tank and convert. Anyone answering no to the first two, or yes to the third, is an excavation. Send us the answers rather than your conclusion, and we will check our read against yours. ### How much do you pay for a basement conversion lead? A fixed fee per accepted lead, at one of two tiers: the raw rate for a lead that meets the acceptance standards, and a higher qualified rate when it also carries the scope, property and professional-appointment detail on this page. The current figures are published on the affiliate rate card rather than here, so there is only ever one number to check, and they are indicative and subject to postcode and volume. ### Do party wall and planning details really change what you pay? Yes, more than anything else except the scope itself. An appointed structural engineer, notices served on adjoining owners, or a basement impact assessment in progress tell a specialist the project is funded and dated, which is exactly what the qualified tier is for. Ask them as optional questions: an owner with nothing to report still clears the raw tier, and one who has something to report costs you a single extra field. ### What happens if you reject one of my leads? You get the decision within 48 hours with the reason named from a fixed, published list rather than a vague quality note, and you can appeal it. Nothing outside that list can be used to reject a lead, and nothing sits pending while you wonder. A rejected lead stays yours to place elsewhere, and your rolling acceptance rate is in your portal so you can see which source is costing you. --- Source: https://aceleads.co.uk/affiliates/sell-basement-conversion-leads Last reviewed: 2026-08-13 Contact: info@aceleads.co.uk AceLeads is a UK-registered business.