Your monthly pipeline of quarry & underpinning projects in Paris
Every week, Sous-sol Paris generates hundreds of reports for owners who have detected a quarry or gypsum risk beneath their building. We pass on the hot leads — the ones requesting a quote for works.
The market: 770 km of quarries beneath Paris and a surge in demand
Paris and its inner suburbs contain more than 770 km of underground galleries left by the historic extraction of Lutetian limestone and Antediluvian gypsum. Every year, several dozen sinkhole (fontis) (localised collapses) are recorded by theInspection Générale des Carrières. Owners are becoming aware of the risk and are actively looking for solutions.
Since recent incidents in the 13th, 14th, 15th and 19th arrondissements received media coverage, assessment requests have soared on our platform — and a significant share of “high risk” reports leads to a request for a quote for works (backfill injection, underpinning, micropiles, jet grouting).
🎯 Pre-qualified leads
Every lead we pass on to you has already bought an assessment report (€15) and explicitly asked to be put in touch with specialist companies. No more cold calling.
📍 Geographic exclusivity
One lead = one address = one buyer only. You are never put up against three other homebuilders on the same case. We also filter by arrondissement or zone to match your coverage area.
💰 Verifiable ROI
An underpinning project in Paris costs between €15,000 and €500,000 depending on its scale. A single project won more than pays for several lead packs. Most of our partners convert 1 lead in 8 to 10.
Return on investment calculation
Here is a realistic scenario based on the averages observed with our active partners:
| Item | Pro Pack (50 leads) |
|---|---|
| Pack cost | 639 € |
| Cost per lead | 12,78 € |
| Average conversion rate (1 in 8) | ~6 projects signed |
| Average project value | ~28 000 € |
| Potential revenue generated | ~168 000 € |
| ROI multiple | 263 × |
Indicative figures based on averages observed with our active partners. Results are not guaranteed and depend on your sales capability, your pricing and your service area.
Lead packs — no commitment
Starter
10 qualified leads · €15.90 / lead
- 10 Parisian owner leads
- Full contact details (name, email, phone, address)
- Full assessment report included
- Documented risk level
- Weekly delivery
Pro
50 qualified leads · €12.78 / lead
- 50 leads over a maximum of 3 months
- Filtering by the arrondissements of your choice
- Filtering by minimum risk level
- Monthly pipeline report
- Priority support
- Geographic exclusivity by address
Premium
200 qualified leads · €9.99 / lead
- 200 leads over a maximum of 6 months
- Advanced geographic and risk filtering
- API access for CRM integration
- Dedicated account manager
- Weekly pipeline report
- Delivery priority on “urgent” leads
Types of works covered by our leads
Depending on the assessment, the owners we pass on to you are looking for experts in the following services:
Backfill injection
Filling cavities by injecting grout (mortar, flowable concrete, expanding foam) under controlled pressure. The benchmark technique for stabilising a cavity at shallow to medium depth.
Underpinning
Strengthening existing foundations by widening, prestressed needle beams or sheeted shafts. Required where the structure is already affected by differential settlement.
Micropiles
Small-diameter bored piles (100-250 mm) transferring the building loads to a stable soil layer beneath the quarry. The preferred solution on constrained urban sites.
Jet grouting
High-pressure injection of cement grout to create columns of treated soil. Suited to heterogeneous ground and gypsum dissolution.
G1 / G2 / G5 geotechnical study
Preliminary engineering missions (standard NF P 94-500). Geotechnical consultancies and engineering firms are also welcome in our partner programme.
Core drilling & endoscopy
Visual inspection of cavities before works. Small specialist firms welcome.
How our lead deliveries work
- You choose your pack and set your filters (arrondissements, minimum risk level, owner’s stated budget, urgency).
- Sous-sol Paris identifies the owners who, after reading their assessment report, tick the box “I would like to be put in touch with a specialist professional”.
- We send you by email every lead matching your filters, including: identity, contact details, address, risk level, age of the building and a direct link to the assessment report.
- You contact the owner within 48h (fast response times convert 3× better) to propose a technical visit and a quote.
- Monthly report : you receive a tracking dashboard (leads received, conversion rate, reported revenue generated).
Zones with high lead volumes
Our track record shows a concentration of requests in the arrondissements that were historically quarried:
- 13th arrondissement (Gobelins, Butte-aux-Cailles, Place d’Italie) — Lutetian limestone
- 14th arrondissement (Denfert, Plaisance, Alésia) — Lutetian limestone
- 15th arrondissement (Vaugirard, Convention) — Lutetian limestone
- 5th and 6th arrondissements (Panthéon, Odéon) — historic former quarries
- 18th / 19th / 20th arrondissements (Montmartre, Belleville, Ménilmontant, Buttes-Chaumont) — Antediluvian gypsum
- Petite Couronne : Ivry, Le Kremlin-Bicêtre, Gentilly, Arcueil, Bagneux, Malakoff, Vanves, Issy-les-Moulineaux, Clichy, Bois-Colombes
Frequently asked questions
Are the leads exclusive?
Yes, each address is sold to a single partner. With us, you are never put up against several homebuilders on the same case.
What happens if a lead is unreachable or fraudulent?
We guarantee the quality of our leads. If a lead is clearly unreachable (invalid email, disconnected phone, false address) or fraudulent, it is replaced free of charge simply by reporting it within 30 days.
What is the lead delivery time?
Delivery is weekly for the Starter and Pro packs, and within 48h for emergencies flagged “active sinkhole (fontis)” on the Premium pack.
Can I change my geographic filters?
Yes, you can change your zones and criteria at any time from your dashboard.
Business invoice?
Yes, an invoice including deductible VAT (20%) is generated automatically in your company’s name.
GDPR compliant?
Yes, every owner explicitly consents to their contact details being passed to a qualified professional. Time-stamped consent is retained and legally enforceable.
Join the homebuilder / construction waiting list
Private demo version — leave us your details and we will get back to you when we open. No payment required.