Greater London · England
New-build mastic & snagging in Woolwich, Greater London
Plot mastic for developers and snagging failed sealant in new homes for homes and businesses in Woolwich and across Greater London. Fully insured, ARBOMaster approved and guaranteed for a year.
- Cracked sealant around new window and door frames
- Skirting joints opening in the first winter
- Cracks appearing as a new home settles
New build mastic in Woolwich
Our new-build work comes in two parts: plot mastic for developers, and putting right failed sealant for people who’ve bought a new home. Both get the same care over preparation, because that is what rushed new-build sealant usually lacks. We are often asked to deal with gaps behind new kitchen upstands and second-fix sealing on new plots, across show homes, plot handovers and bathrooms & en suites.
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.
- Where
- Woolwich (SE18, E16, SE7)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Quote
- A clear quote up front
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
How the job changes by surface
Kitchens
Worktops in new homes can move slightly as the house dries, which opens gaps along the back. We reseal them with a flexible sealant.
Skirting and floors
Floors and skirting move as the house dries and the heating runs. We use a flexible product rather than caulk in a colour to suit.
What we do, step by step
Before we leave, we go over the finished joints with you. The visit itself generally takes a few hours in a single home, depending on the size of the job. In a London area like Woolwich, the main things to plan are parking and access: tell us about permits, visitor bays or off-street space, which floor we’re working on and whether there’s a lift.
- Each joint is checked for movement before we start.
- Old sealant is cut out and the joints cleaned.
- We make sure the joints are dry and prime them if needed.
- Baths are filled with water, then the new sealant is applied.
- We check every joint and leave you with the cure times.
How to prepare
- For business premises, tell us about site rules or sign-in
- Let us know about stairs, lifts or work at height
- Mention if the joints have been sealed before
Getting a quote
To get a quote, call 0345 464 0079 or email us with the location and a short description of the problem. You’ll have a clear quote before work begins.
Read more
Keeping the joints in good condition
Aftercare is simple:
- Keep water off fresh sealant until it has cured
- Open a window or run the fan after bathing
- Resist patching a failed seal with a tube from the DIY shop
- Wipe joints with warm soapy water
Wipe the sealant with warm soapy water. Keep scourers and harsh chemicals off it as they wear the bead.
Don’t let the snagging period run out with sealant problems unreported. After that, putting it right may fall to you so report it promptly.
New homes and floors in Woolwich
Many of London’s new homes are flats in bigger developments, where snags may need reporting through the developer or the managing agent. Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
If you’ve bought a new home near Woolwich Dockyard station, the sealant around baths, showers and frames is worth checking in the first year or two.
Woolwich is about 6 miles south-east of Leyton, in Greater London. Jobs in Woolwich get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. Woolwich is one of 764 places in Greater London we cover. We also work in London, about 7 miles from Woolwich.
We cover every part of SE18, E16 and SE7 for new build mastic and the streets around it. We cover properties on Market Street, Woolwich High Street and Beresford Square Market Place and the roads around them. Neighbouring places we cover for new build mastic include Plumstead (1 mile east), Charlton (1 mile west), New Charlton (1 mile west), Shooter's Hill (1 mile south) and Kidbrooke (2 miles south-west). Larger places within reach include London (7 miles west), City of Westminster (9 miles west), Marylebone (9 miles west), Kensington (11 miles west), St Pancras (8 miles west) and Shoreditch (7 miles north-west).
Around Woolwich
Locally, jobs take us to homes and businesses close to Woolwich Common, Oasis Academy Silvertown and Oasis Academy Silvertown and the streets around them. There’s a railway station in Woolwich itself: Woolwich Dockyard station. Nearby you’ll also find Royal Artillery Museum (0.5 miles north-east) and British Hospital for Mothers and Babies (0.5 miles west). Not far away are Gilbert's Pit.
Work for landlords, hotels and businesses
In hotels, rooms out of use cost money, so the work can be planned room by room. Hotel work is part of what we do, alongside homes and businesses.
We also work for property managers and facilities teams. Several sites can be quoted together, and we’re fully insured for the work.
Should I try it myself first?
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it lifts and traps water and mould underneath. All the old material has to come out first.
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Questions from Woolwich
I let a flat near Woolwich Dockyard station. Can you help?
Yes, we work for landlords and agents. You can call 0345 464 0079 or email us with the address and a few details, and we’ll give you a fixed price before any work starts.
Can parking be tricky for a visit in Woolwich?
Parking in Woolwich, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly, so mention what’s available when you book.
Where are you based?
Mr Mastic is based in Crawley. We cover Woolwich and the rest of Greater London, along with the rest of our area.
Is it messy?
Tidy work is part of the job. We protect what’s around the joints.
How long does new build mastic take?
A typical job takes anything from a few hours to several days, depending on the number of plots. We will confirm how long when we quote.
Can I do it myself?
Some simple jobs can be done by a careful DIYer. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
Do you hold any approvals?
Yes. We are approved under the ARBOMaster scheme, the approved applicator scheme for Arbo sealants.
Do you remove the old sealant?
Yes, always, and completely. New silicone does not stick to old silicone, so any old material comes out before anything new goes in.
What affects the cost of new build mastic
For a quick quote, just ask. The main things that affect it are:
- Whether old sealant or filler has to be cut out
- Whether the work is at height
- The type of sealant required
- The size of the job
Every job is a little different, so each one gets its own quote. Size, access and the product the joint needs all make a difference.
Helping us quote
You do not need to know the technical terms. Just tell us:
- The rough size of the job
- Access, such as stairs, a lift or height
- If someone has resealed it before
- Where the property is
Call for a quick quote, or email us if that’s easier. Describe what needs sealing and we will explain what’s involved and send you a clear quote.
Places near Woolwich
Other services in Woolwich
Do you need new build mastic in Woolwich?
Fresh sealant can be knocked or cut by trades finishing off. If it’s disturbed before curing, the joint can be left weak, and the problem shows up after you move in.
These are the problems we are asked about most:
- Internal frame sealant that has split
- Sealant that never bonded to the surface
- Untidy sealant flagged on a snagging list
- Leaking shower tray seals in a new home
Woolwich is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Before booking anyone
- What the cure time is
- What preparation is included
- What happens if the job turns out different
- Whether VAT is included