Greater London · England
New-build mastic & snagging in Greenhill, Greater London
Our applicators work in Greenhill on plot mastic for developers and snagging failed sealant in new homes. Old sealant removed completely, joints prepared properly and a one-year guarantee.
- Skirting joints opening in the first winter
- Shower seals failing in the first year or two
- Plot mastic for developers ahead of handover
Surface by surface
Kitchens
Worktops in new homes can move slightly as the house dries, which opens gaps along the back. A fresh flexible bead closes them.
Windows and doors
Draughts around new frames are often a sealant gap. We look at the joints and reseal where needed.
About our new build mastic in Greenhill
A new build should have a neat, sound bead at every joint. When the finish is smeared, patchy or already cracking, it’s worth putting right early, before water gets into the floor or walls. We are often asked to deal with messy sealant that spoils new finishes and gaps between new skirting and floors, across show homes, skirting & floors and plot handovers.
London homes range from new-build flats to period conversions with new floors laid over old boards. Wherever a floor meets a wall, a skirting or a threshold, the joint has to allow for movement, in Greenhill as anywhere.
The work is covered for a year after we finish. If anything isn’t right with it, phone 0345 464 0079 or drop us an email.
- Location
- Greenhill (HA1, HA3, HA2)
- Region
- Greater London
- Cover
- 12 months on all our work
- Price
- A clear price before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
What we do, step by step
We bring everything the job needs with us. Once we’ve agreed what’s being done, we protect the area and start. It normally takes a few hours for most snagging lists, longer for a run of plots. In Greenhill, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- We start by going through the snagging items or plot schedule with you.
- Every bit of the old builder’s sealant is cut out down to clean surfaces.
- Joints are vacuumed and cleaned of building dust.
- We prime where needed and apply a sealant suited to each joint.
- Each bead is tooled and the cure times explained.
How to prepare
- Plan for the work area to be out of bounds to pets and children
- Tell us about access, such as stairs, a lift or high-level joints
- Clear items away from the joints we are working on
How to get a quote
For a quote, ring 0345 464 0079 or email us with the location and a short description of the problem. You’ll have a clear quote before any work starts.
Related advice
Work for landlords, hotels and businesses
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance that we can handle for you.
Can I do it myself?
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions.
Sealing over old silicone is the commonest DIY error. Silicone does not stick to old silicone, so it peels away and traps moisture behind it. Everything old must be removed first.
Nearby places to Greenhill
More services for Greenhill
Questions from Greenhill
Is parking an issue for new build mastic in Greenhill?
Parking in Greenhill, 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.
I let a flat near Harrow-on-the-Hill station. Can you help?
Yes, landlords and agents are among the people we work for. You can phone 0345 464 0079 or email us with the details for a clear quote.
Why does sealant fail so quickly in new builds?
It’s common, and there are normally two reasons: movement as the house dries and settles, and sealant laid onto dust without primer. Cutting it out and resealing properly fixes both.
Are you an approved applicator?
Yes. We are an ARBOMaster approved applicator, the approved applicator scheme for Arbo sealants.
Where do you work from?
Our base is Crawley. We work across South East England, London and Scotland.
Do I need to be at home?
Access is agreed with you when the job is booked. Indoors, that generally means someone at home.
What colour sealant will you use?
White and clear are the most common, but sealant comes in other colours too. We match the colour to the finish before we begin.
Will you just run a new bead over the existing one?
No. New silicone won’t bond to old silicone, so it soon lifts and traps water. We cut the old bead out completely.
Quotes for new build mastic in Greenhill
We do not publish a price list. The quote depends on:
- Whether old sealant or filler has to be cut out
- Whether there’s mould to deal with
- Whether the work is at height
- Which sealant suits the joint
Instead of a standard rate, we price the job in front of us: the amount of work, the old material and the access. You’ll know the price before we begin.
Asking for a quote
Photos help, but a description is a good start. Try to tell us:
- The problem you’ve noticed
- Access, such as stairs, a lift or height
- Roughly how big the job is
- Pictures of the joints, sent by email
Asking for a quote is easy: let us know what needs doing and where and its rough size. A few photos by email make the job easier to understand, and we will come back to you with a quote.
Aftercare tips
After the cure time, these simple habits help:
- Look at the sealant regularly in the first couple of years
- Keep water off fresh sealant until it has cured
- Don’t wait for the house to settle if water is getting through
- Keep photos and emails about snagging items
Follow the cure time we give you before the area gets wet. Silicone is normally left for about a day.
A seal that splits early is often a sign of movement. Getting it resealed properly, and any movement checked, stops it recurring.
Joints and finishes in Greenhill homes
The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Much of London’s new housing is flats in larger developments, where snags may need reporting through the developer or the managing agent.
For new homes near Harrow-on-the-Hill station, it’s worth checking the sealant early, while snags are still fresh.
Greenhill is about 1 mile north-east of Harrow, in Greater London. We carry out new build mastic for householders, landlords and businesses in Greenhill. 764 places in Greater London are on our list. Our London page covers work nearby.
Postcode districts we cover here for new build mastic: HA1, HA3 and HA2. We cover properties on Lyon Road, Hill Road and Byron Road and the roads around them. Other places close to Greenhill include Wealdstone (1 mile north), Northwick Park (1 mile south-east), Harrow (1 mile south-west), Kenton (1 mile east) and Roxeth (1 mile south-west). Within a short drive, we also cover London (12 miles south-east), City of Westminster (9 miles south-east), Marylebone (9 miles south-east), Kensington (8 miles south-east), St Pancras (10 miles south-east) and Shoreditch (12 miles east).
Landmarks near Greenhill
Typical jobs here are in homes near Royal Oak pub, Northwick Park and Harrow High School and the streets around them. There’s a railway station in Greenhill itself: Harrow-on-the-Hill station. A little further out are St. Anns (under half a mile south-west) and Hilfield Castle (4.8 miles north). Not far away are Masons Field and Northala Fields.
What we’re called out for in Greenhill
The first winter with the heating on dries a new home quickly. Gaps open along skirting, frames and worktops and cracks appear in the sealant.
Common reasons people contact us include:
- Cracks appearing as a new home settles
- Worktop and upstand sealant coming away
- Sealant that never bonded to the surface
- Sealant work across a run of new homes
Greenhill is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Questions to ask before you book
- How much experience the applicator has
- Is VAT in the price?
- Is the old sealant removed completely?
- What product goes in the joint