Greater London · England
Streatham New Build Mastic
New build mastic in Streatham from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Cracked caulk along new skirting
- Plot mastic for developers ahead of handover
- Sealant that never bonded to the surface
New build mastic in Streatham
For builders and developers, we work through plots to the schedule you give us. We seal bathrooms, kitchens, windows, doors and skirting so plots are ready to hand over with a sealant suited to each area. If you have sealant work across a run of new homes and cracked sealant around new window and door frames, we can put it right, whatever the surface.
New flats are going up across London, many of them in larger developments. Snagging there often goes through the developer or managing agent, and shower seals that fail early, skirting joints that open up and gaps at thresholds are all common snags.
Our work is backed for twelve months.
- Location
- Streatham (SW16, SW2, CR4, SW12)
- Region
- Greater London
- Cover
- 12 months on all our work
- Price
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
How it works
On the day, we start by going over the job with you, so there are no surprises. Surfaces next to the work are protected before work begins. The work generally takes anything from a few hours to several days, depending on the number of plots. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. If the building has a concierge, managing agent or access rules, tell us when you book.
- We go through the snagging list or plot schedule and agree the joints to do.
- We cut out every bit of the failed or messy sealant.
- Each joint is cleaned of dust and grit, then primed if required.
- A sealant chosen for each area goes in and is tooled smooth.
- We check every joint and tell you how long each needs to cure.
Before we arrive
- On commercial sites, let us know about site rules
- Mention any tricky access
- Plan for the work area to be out of bounds to pets and children
Get a quote
If you’re in Streatham and need new build mastic, ring 0345 464 0079 or send us an email. Tell us what the problem is and where, and you will get a clear quote before we start.
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Common problems we fix in Streatham
Sealant applied onto damp surfaces doesn’t bond well. Site programmes don’t always leave time for joints to dry first.
Common reasons people contact us include:
- Sealant that never bonded to the surface
- Skirting joints opening in the first winter
- Second-fix sealing on new plots
- Frame joints opening as the plaster dries
Streatham is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
What your quote should include
- How the colour is chosen
- What the quote includes, VAT included or not
- How the joint is cleaned and prepared
- What the cure time is
DIY sealant or a professional job?
Sealing over old silicone is the commonest DIY error. New silicone won’t bond to old, so it lifts and traps water and mould underneath. All the old material has to come out first.
If you’ve already had a go yourself, that’s fine. We remove it and do the joint properly.
When something else is needed
Some problems need a builder, plumber or other trade rather than us:
- Leaking fittings rather than failed sealant
- Cracked trays, tiles or worktops
- Disputes or warranty claims with your builder
If you’re not sure, just ring 0345 464 0079 or email us and we will give you a straight answer.
Surfaces we seal
- Plot handovers
- Windows & doors
- Bathrooms & en suites
- Show homes
- Skirting & floors
- Kitchens
What affects the cost of new build mastic
Every job gets its own quote. These are the things that affect it:
- Mould in or behind the old joints
- The number of rooms or windows
- Whether the work is at height
- Any working-time requirements on site
What it costs depends on the amount of work, how hard the old material is to remove and access to the work. You’ll have a clear quote before any work starts, so you know where you stand.
Asking for a quote
Photos help, but a description is a good start. Please mention:
- Where the property is
- What’s wrong with the joints now
- The rough size of the job
- Any previous sealing or DIY work
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and email photos if that is easy.
New homes and floors in Streatham
London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. Much of London’s new housing is flats in larger developments, where snagging may go through the developer or managing agent.
For new homes near Streatham station, it’s worth checking the sealant early, while snags are still fresh.
Streatham is about 5 miles south of London, in Greater London. From the centre of Streatham to the outskirts, new build mastic is available for homes and businesses alike, from flats and houses to offices and hotels. Streatham is one of 764 places in Greater London we cover for new build mastic.
All of SW16, SW2, CR4 and SW12 is within our area for new build mastic, from the main roads to the quietest streets. Local streets include Stanthorpe Road, Gleneagle Mews and Madeira Road, and we cover them all. Streatham is on the A205 and A216, so it’s easy for us to get to. Other places close to Streatham include Streatham Park (1 mile west), Furzedown (1 mile west), Streatham Hill (1 mile north), Hyde farm estate (1 mile north) and Grange Mills (1 mile north-west). Within a short drive, we also cover London (5 miles north), City of Westminster (6 miles north), Marylebone (6 miles north), Kensington (6 miles north-west), St Pancras (7 miles north) and Shoreditch (7 miles north).
Around Streatham
Typical jobs here are in homes near Bishop Thomas Grant Catholic Secondary School, Streatham Common and Waldorf School of South West London, among other places. There’s a railway station in Streatham itself: Streatham station. Nearby you will also find Clockworks Museum (1.1 miles east) and Southside Wandsworth (3.3 miles north-west). Green spaces nearby include Knight's Hill and Battersea Park Lake.
Common questions in Streatham
Do you work for landlords with property near Streatham station?
Yes, rental work is part of what we do. You can call 0345 464 0079 or drop us an email with the address and a few details, and we will give you a fixed price before any work starts.
Is parking an issue for new build mastic in Streatham?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. That way the visit can be planned around it.
Are you fully insured?
Yes. Mr Mastic is fully insured.
Is there any odour?
Some sealants have a smell while they cure, but it fades. Ventilation helps.
Can you do plot mastic on a new development?
Yes. We carry out plot mastic and second-fix sealing for builders and developers. Send the schedule and any specification and we will give you a quote.
Can you match the sealant colour to my new kitchen or bathroom?
Most bathroom joints are white or clear, but other colours are available. We match the colour to the finish and agree it with you.
How long will you be here?
Most jobs take a few hours in a single home. We’ll confirm how long when we quote.
Are you ARBOMaster approved?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we are part of it.
What the job involves on each surface
Show homes
We can refresh show-home sealant that has discoloured or been knocked. The old bead comes out and a clean new one goes in.
Bathrooms and en suites
En suite showers are a common source of leaks into the room below. A proper reseal keeps water in the tray.
For landlords and businesses
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements.
We work for letting agents and landlords as well as householders. Sealant work between tenants keeps a property looking cared for.