Construction and new-build mastic in Coldharbour, Greater London
Mastic packages for new-build and refurbishment projects in Coldharbour. CHAS accredited and fully insured, with a 12-month guarantee.
- A mastic package split between trades with no clear owner
- Missed perimeter joints on a new elevation
- Internal caulk splitting as the building dries out
Construction mastic for Coldharbour sites
Share the site address and what’s failing, and we’ll reply with a fixed quote or arrange a visit.
Construction mastic in Coldharbour, done properly
Site managers want applicators who turn up with the right cards and paperwork. We are a Constructionline member and CHAS accredited, and every applicator holds a CSCS card. Tell us what site paperwork you need (RAMS, insurance certificate, CSCS details) and we will confirm with the quote. Site teams most often ask us about bath and shower joints scraped during the final clean and inconsistent sealant finishes from plot to plot, across floor and skirting junctions, window and door perimeters and brick and block movement joints. Whoever orders the work in Coldharbour, the brief is usually the same: a fixed quote, no surprises on site and a 12-month guarantee behind the result.
A great deal of London construction is refurbishment of occupied or part-occupied buildings, alongside new blocks. Replacement windows, recladding and fit-outs leave perimeter and facade joints to seal, often next to people still using the building, so tidy, well-planned work matters.
We stand behind the joints we seal with a 12-month guarantee. It covers how we prepared and applied the sealant, and we come back if anything isn’t right.
- Place
- Coldharbour (SE9, BR7)
- Region
- Greater London
- Guarantee
- A 12-month guarantee
- Quote
- Quoted before any work starts
- Call
- 01277 525 020
- Page updated
- 3 November 2026
Work for main contractors and building owners
Hotels, schools, healthcare sites, offices and retail units book us directly too. We plan around the way the building is used, so the building keeps working while we do.
As a CHAS accredited contractor and Constructionline member, we are straightforward to vet for your supplier list. We are fully insured, and our insurance certificate can go with the quote.
How the job changes by surface
Kitchens and utility areas
Commercial kitchens often need hygienic or food-safe sealants. We follow the specification and seal to a smooth, cleanable finish.
External facade and movement joints
External movement joints often need primer, depending on the substrate. We prime where the manufacturer specifies, and seal only with a dry joint inside the product’s temperature range.
Common questions from Coldharbour clients
Is a hospital such as Eltham Community Hospital somewhere you can work?
Yes. We work in healthcare settings as well as offices and schools. Before anything starts, the estates team agrees permits, inductions and infection-control measures with us.
Can you work at a site such as Green Lane Business Park, by Coldharbour?
Yes. We cover Coldharbour and the area around it, including industrial estates, business parks and retail parks such as Green Lane Business Park. Send details of the unit and the work through our quote form for a quick quote.
What accreditations do you hold?
CHAS and Constructionline are both in place, and our applicators hold CSCS cards. We are fully insured for public liability.
When can the area be used after sealing?
We’ll confirm how long the chosen product needs to cure, and sign any area that should be left alone.
When can you be on site?
Give us your site hours and any access windows in your enquiry, and we will plan around them. You can reach the office between 8am and 5pm, Monday to Friday.
Do you use the sealant named in the specification?
We follow the specified sealant. Product standards such as BS EN 15651 are often named in specifications.
How long does a job like this take?
That varies with the scale of the job, though a typical visit typically takes a day or two on a small fit-out and several weeks on a large multi-storey package. For bigger or phased jobs, we’ll set out a timescale with the quote.
What sets the cost
To price the job, we consider:
- Working within restricted access windows
- Any access equipment needed
- Which sealant the job calls for
- Backing rod, priming and other preparation
We don’t publish prices, since every building and every scope is different. For a fixed figure, call for a quote and we will price your job on its own details.
Details that help us quote
Good information means a firmer quote. When you get in touch, include:
- Anything awkward about access or site hours
- The postcode of the building
- Whether an asbestos survey exists
- Rough lengths or quantities, or drawings if you have them
Tell us about the building, the joints and when you need the work done, and a fixed quote will follow. The easiest way is to ring 01277 525 020 or email us.
Maintenance after handover
Problems stay small when the joints are checked regularly. Specifically:
- Don’t force external sealing on a damp or frosty day
- Brief the final clean team to avoid blades near sealant
- Keep product details for future maintenance
- Don’t schedule sealing before decorators and flooring are done
The package carries our 12-month guarantee for workmanship. Damage by others isn’t a workmanship fault which is why protection after sealing matters.
Oversized gaps are a problem better caught early. Filling a wide gap with sealant alone sets up a failure so packing or adjustment by the installer comes first. We flag them as soon as we see them.
Our process
Diagnose, treat, sign off: that’s the shape of every visit. First comes an inspection and agreement on scope, then the work is carried out to the specified product and detail, and we finish with a walk round so the work can be signed off. All of Greater London is in the ULEZ, and kerbside space in Coldharbour can be scarce. Let us know about any on-site parking or loading arrangements when you send the job details.
- 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.
- Problems we find, such as oversized gaps, are raised right away.
- The package is closed out, snags cleared and backed by our 12-month guarantee.
Preparing the site
- Have the specification and drawings to hand
- Flag any permit to work we’ll need
- Arrange parking or a loading space
Request a quote
Every job follows the same four steps: send details, get a quote, we seal, guaranteed. To take the first step, call 01277 525 020 or email us.
Related advice
Why deal with it now?
Sealing over damaged or contaminated new joints might save a day. New sealant laid on old or dirty sealant has nothing to bond to. We cut out and redo the joint properly. Repeat call-outs disrupt occupied London buildings, so cutting the old sealant out fully and doing it right once is the better route.
The work involved drives the cost: stripping out, preparation, sealing, access and phasing. Call for a quote and we will explain how it’s made up.
What you get with us
- Specification-led, product-correct work
- CHAS accredited
- One phone line for London, the South East and Scotland
- Work carried out by CSCS-carded applicators
Take a look at what affects the cost or our accreditations and insurance.
Towns and villages near Coldharbour
Also in Coldharbour
Contractors’ notes for Coldharbour
Several hotels sit less than 2 miles from Coldharbour. Hotel schemes tend to have fixed reopening dates, so the mastic is programmed tightly with the other trades. As part of Greater London, Coldharbour is inside the ULEZ, which applies to every van on site. Add booked deliveries and tight storage, and the mastic package needs planning with the site team.
Recladding or extending a unit at a site like Green Lane Business Park, 0.6 miles north-east of Coldharbour, brings panel joints and frame perimeters into the programme. For a contractor at a hotel such as Baring Hall Hotel (1.3 miles west of Coldharbour), the mastic often has to be finished before a reopening date. For a contractor working at a hospital such as Eltham Community Hospital, which lies north of Coldharbour, perimeter and facade sealing is planned around patients and deliveries.
Coldharbour is about 4 miles north-west of Orpington, in Greater London. We cover commercial sites throughout Coldharbour, whether it’s a single job or part of a planned programme. Our Greater London coverage takes in 764 places, from busy centres to rural villages. There’s a separate page for London, about 8 miles away.
We take on mastic packages across the SE9 and BR7 postcode area. If your site is on Green Lane, Horley Road and Dorset Road or close by, send details and we’ll quote for mastic packages. Nearby places we also cover include Mottingham (1 mile west), Chinbrook (1 mile west), New Eltham (1 mile north-east), Eltham (1 mile north) and Middle Park (1 mile north-west). A short drive away, we cover London (8 miles north-west), City of Westminster (11 miles north-west), Marylebone (10 miles north-west), Kensington (12 miles north-west), St Pancras (10 miles north-west) and Shoreditch (9 miles north-west).
What’s near Coldharbour
In Coldharbour, that means premises near Elmstead Wood and St Thomas More Catholic Comprehensive School, among other places. For rail, the closest station is Mottingham station, roughly 0.6 miles north of the centre. Other landmarks nearby include The Glades (2.4 miles south-west) and Metropolitan Police Museum (2.2 miles east). Green spaces nearby include The Tarn and Summer Hill.