Commercial Mastic Contractor for Westminster & the City of London
Stone façades, glazed office fronts and offices sealed after the fit-out trades in the Square Mile and the West End, from a sealant contractor already working in the City.
The new City of London law courts at Salisbury Square
Just off Fleet Street, we’re sealing the external window frames where the natural stone façade meets each frame, in a non-staining silicone chosen for stone.
Portland stone, glass and a lot of listed fabric
The City and Westminster hold some of the most demanding façades in the country. Towers of curtain walling and structural glazing sit beside Portland stone offices, Victorian banks and the Inns of Court around Temple. Holborn and Farringdon mix converted warehouses with new office blocks near the Elizabeth line.
Each needs a different approach. Glazing needs a low-modulus silicone that takes movement. Stone needs a sealant that won’t bleed into the face. Older brick and stone in conservation areas may need a softer, lime-compatible product.
Sealant work we price in central London
Sealing Cat A & Cat B office fit-outs
We come in after the fit-out contractor: perimeter seals to partitions and glazing, washrooms, tea points and kitchenettes, and air-tightness sealing.
Curtain walling & glazing
Weather seals and perimeter joints on glazed façades and structural glazing, from MEWPs or scaffold.
Façade sealant →Stone-to-frame perimeters
Window perimeters on stone and brick elevations, colour-matched and kept off the stone face.
Window & door mastic →Retail & hospitality
Shopfronts, and restaurants and bars sealed once the fit-out contractor has finished, with hygienic and food-safe sealants in kitchens.
What you get with us on a City or West End job
We’re a Bedford-based contractor, so we won’t pretend to be round the corner. What we bring is the paperwork and experience central London sites expect:
- Current City experience: on site at Salisbury Square since June 2026
- Robert’s CSCS Blue Skilled Worker card (Sealant Applicator, NVQ2), IPAF 3a/3b and PASMA
- Constructionline Silver; £10m employer’s liability and £5m public liability / professional indemnity
- RAMS on request; no RIDDOR incidents in three years
- Over 20 years in construction
Insured & pre-qualified
Peace of mind for homeowners, builders and main contractors.
- £10m Employer’s LiabilityInsurance cover
- £5m Public Liability & Professional IndemnityInsurance cover
- Constructionline Silver member
- CSCS Skilled WorkerSealant Applicator (NVQ Level 2)
Over 20 years in construction
Products we use
Professional-grade sealants and adhesives from leading manufacturers.
Brand names and logos are trademarks of their respective owners and are shown to identify products we use. No endorsement is implied.
Districts we cover in the City and Westminster
We take on commercial sealant work across both, and the neighbouring boroughs too: Camden & Islington to the north, Southwark & Lambeth across the river, and Kensington, Chelsea & Fulham to the west. For all our London work see the London page.
- Square Mile
- Fleet Street
- Temple
- Holborn
- Farringdon
- Clerkenwell edge
- Moorgate
- Aldgate
- Mayfair
- Soho
- Victoria
- Marylebone
- Paddington
- Pimlico
The kind of detail City façades need
Westminster and City sealant work: common questions
Do you do commercial sealant work in Westminster and the City?
Yes. We seal partition walls, washrooms and offices after the fit-out trades, plus stone and glazed façades, shopfronts and new-build schemes, for fit-out contractors and main contractors. We’re on site now at the new City of London law courts at Salisbury Square.
Can you work within the noise and hours rules for central London sites?
Yes. Central London sites usually run to hours set by the council or a Section 61 consent, with booked delivery slots. Sealant is quiet work, but cutting out old joints isn’t, so we plan noisy tasks into the permitted windows. Tell us the site’s hours when you enquire.
Do you seal listed buildings and stone in conservation areas?
Yes, with care over product choice. Natural stone such as Portland stone can stain with the wrong silicone, so we use non-staining sealants and primers the manufacturer approves for stone, and lime-compatible products on older masonry where the spec calls for them.
Can you work out of hours in an occupied office?
Yes. Evening or weekend working can be arranged when we’re sealing offices in live, occupied buildings, so tenants aren’t disturbed. Agree the hours with us at quote stage.
How do you get materials onto a City site with no parking?
We plan around it: booked delivery slots, loading bays where the site has one, and only the materials needed for the next few days. Sealant is light, so we don’t need much storage.
Working on a City or West End scheme?
Send elevations, the spec or a fit-out drawing to office@pioneersealants.co.uk. We’ll come back with questions or a price.
- Opening hours
- Monday – Friday8:00am – 6:30pm
- Saturday9:00am – 4:00pm
- SundayClosed
