Construction and new-build mastic in Forest Hill, Greater London
Construction mastic in Forest Hill, backed by over 20 years in commercial sealing. Fully insured, with a 12-month guarantee.
- External joints sealed in damp or cold conditions that are now failing
- Snag items on joints that need redoing before handover
- Sanitary sealant damaged by following trades
Construction mastic in Forest Hill
Photos, a specification or a quick description of the joints is enough to start a fixed quote.
Forest Hill: questions and answers
Can you take on a job at a hospital such as University Hospital Lewisham?
Yes. We work in healthcare settings as well as offices and schools. The estates team’s permit system and infection-control rules come first, and the work is planned around them.
Is Clyde Vale Industrial Estate, near Forest Hill, within your area?
Yes. Estates, retail parks and business parks around Forest Hill, Clyde Vale Industrial Estate among them, are all within reach. Photos and a short description are enough for a first look.
Which sealant will you use?
If the job is specified, we follow the specification. Otherwise, we recommend a product to suit the joint’s movement, the substrate and the conditions, following the manufacturer’s guidance.
What will the job cost?
That depends on the job: the volume of work, the access, the specified product and how it’s phased. Call for a fixed quote and we will price it properly.
Do you take on mastic snagging only?
Yes, we can. Send the snag list or photos and we will price it, with the work timed to your handover date.
Can fire-rated sealing at service penetrations be included?
We install fire-rated sealant where it is the specified product. We will flag if the detail needs a different product.
Are you insured?
Yes. We are fully insured, and the certificate can go with your quote.
Construction mastic for commercial buildings in Forest Hill
Mastic Doctor has been a subcontractor on construction projects for over 20 years. Quantities come off the drawings, the sequence is agreed with the site manager and the work follows the trades. To price a package in Forest Hill, send drawings and the specification through our quote form. We work on sanitary and kitchen joints, cladding and panel joints and floor and skirting junctions, and the failures we’re asked to look at most are caulk cracking where joints are moving more than expected and existing joints on a refurb that need cutting out and resealing. For commercial sealant work in Forest Hill, you deal with one contact from quote to sign-off, whether it’s one building or several.
Around Forest Hill, as across London, much of the work is refurbishing existing buildings as well as building new ones. Replacement windows, recladding and fit-outs leave perimeter and facade joints to seal, often next to people still using the building.
Every job we finish is backed by a 12-month workmanship guarantee, wherever the site is. If a joint we sealed fails because of how it was installed, we come back and put it right.
- Place
- Forest Hill (SE23, SE22, SE26)
- Wider area
- Greater London
- Guarantee
- 12 months on every job
- Quotes
- A fixed quote before we start
- Telephone
- 01277 525 020
- Last updated
- 3 November 2026
After the work
Every sealant joint needs some looking after, and their life depends on movement, exposure, cleaning and use. Our advice:
- Protect sealed areas from following trades
- Don’t schedule sealing before decorators and flooring are done
- Plan external elevations with the weather in mind
- Share drawings and the specification as soon as possible
Any damage after we have finished should go on the snag list right away. We can return to clear snags before handover, priced as part of the package or separately.
Sealing outside when the joint is damp or too cold leads to poor adhesion. Waiting for a dry joint and the right temperature is better than redoing work.
Our process
Diagnose, treat, sign off: every visit follows that pattern. First comes an inspection and agreement on scope, then we prepare and seal each joint with the specified product, and we finish with a walk round so the work can be signed off. For a job in Forest Hill, access comes first: booked loading, goods lifts, the building’s permit system and a spot to keep materials. Send the building rules and access times with your enquiry.
- First we look at the scope on site or from drawings.
- You receive a fixed quote covering scope, products and sequence.
- Site paperwork is confirmed and our CSCS-carded applicators are inducted.
- Sealing follows the programme as areas are released.
- Any frame gaps or issues outside our scope are flagged to the site team.
- Final snagging is completed and the 12-month guarantee applies.
Before we start on site
- Tell us your opening times and when work is allowed
- Clear stock, furniture or equipment away from the joints
- Send asbestos survey details if the building is pre-2000
Get a fixed quote
Send us photographs, drawings or a joint schedule are often enough for a fixed quote. Where a site visit makes more sense, we’ll arrange one.
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Mastic packages on Forest Hill sites
The ULEZ covers the whole of Greater London, Forest Hill included, so site vehicles need to meet its standards or pay the daily charge. Deliveries are booked and storage is tight, so mastic materials come in as needed. A 2-mile radius around Forest Hill takes in several hotels. Hotel schemes tend to have fixed reopening dates, so the mastic is programmed tightly with the other trades.
Projects at schools like Fairlawn Primary School work to term dates, so mastic is programmed tightly. New wings at hospitals like University Hospital Lewisham, 1.6 miles to the east of Forest Hill, bring long runs of window and panel joints to seal.
Forest Hill is about 2 miles south-east of East Dulwich, in Greater London. Anywhere in SE23, it works the same way: send details, get a fixed quote, we seal, and the work is guaranteed. Across Greater London, 764 places are covered, Forest Hill among them.
Postcode districts covered here: SE23, SE22 and SE26. Among the streets we cover are Ewart Road, London Road and Rojack Road. Close to Forest Hill, our area also takes in Honor Oak (1 mile north), Perry Vale (1 mile south-east), Brockley (1 mile north-east), Crofton Park (1 mile north-east) and Dulwich (1 mile west). Bigger towns within reach include London (4 miles north-west), City of Westminster (6 miles north-west), Marylebone (6 miles north-west), Kensington (7 miles north-west), St Pancras (6 miles north-west) and Shoreditch (6 miles north).
Around Forest Hill
Locally, jobs take us to sites close to Allenby Tutorial Trust, Capitol Cinema pub and Harris Girls' Academy East Dulwich. The nearest railway station is Honor Oak Park station, about 0.5 miles north-east of the centre. Nearby you will also find Greenwich Castle (3.1 miles north-east) and Horniman Museum and Gardens (0.5 miles south-west). Green spaces nearby include One Tree Hill and Knight's Hill.
What we can’t put right
Honesty saves time and money. New sealant won’t cure:
- Specifying the product where the designer hasn’t
- Oversized gaps that need packing or adjustment by others
- Damage to finishes by other trades after we’ve sealed
If you’re not sure, just call the office on 01277 525 020 or email the details over and we will give you a straight answer before you book.
Where we work in Forest Hill
- Floor and skirting junctions
- Window and door perimeters
- Cladding and panel joints
- Brick and block movement joints
- Internal decorators’ caulk
- Sanitary and kitchen joints
When to call us in Forest Hill
Dust is the enemy of adhesion on a construction site. Plaster dust, release agents, protective film residue and damp all stop sealant bonding.
Site and facilities staff are often the first to spot these:
- External joints sealed in damp or cold conditions that are now failing
- Cracks opening in caulked internal joints
- Existing joints on a refurb that need cutting out and resealing
- Sanitary sealant damaged by following trades
Projects at colleges like Christ the King: Aquinas Sixth Form College (1.6 miles north of Forest Hill) tend to run to term dates, so the mastic is planned tightly.
What your quote should include
- What site paperwork they can supply
- Their public liability cover
- Do they follow the manufacturer’s priming guidance?
- How the existing material will be dealt with
Nearby places to Forest Hill
What else we do in Forest Hill
General trades versus a specialist
General builders and handymen seal joints, but it isn’t their main trade. A specialist prepares properly, controls joint depth and picks a product with the right movement class, which is what makes a joint last.
The visible bead is only part of the job. Correct depth, the right primer and a sealant matched to the movement are where general trades tend to cut corners.
What affects the price in Forest Hill
Sealant work doesn’t have a standard rate, because every site is different. What we look at:
- Site requirements such as inductions and permits
- Removal of failed or old sealant
- How much there is to seal
- Distance, for remote addresses
Pricing mastic packages depends on how many there are, their condition and the access. Ask us for a fixed quote.
What we need to price the job
A good diagnosis starts with the right details. Tell us:
- The asbestos register, for older buildings
- Where the site is, with the postcode
- Any specification or named product
- Any dates the work must fit around
Specifications, drawings and tender packages are welcome with any enquiry, and we’ll price the work to it. Smaller jobs need nothing more than photos and a few notes.