Greater London · England
Sand Mastic in Northwick Park
Window and door surrounds in Northwick Park need attention? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- A silicone bead on a sash window that spoils the look
- Weathered mastic on the most exposed windows
- Mastic dropping out of the joint
DIY sealant or a professional job?
A DIY attempt doesn’t rule out a professional job. We cut it out and start again.
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
Sand mastic for homes and businesses in Northwick Park
A silicone bead around a sash window can look out of place and isn’t always the right material. Sand mastic is the traditional choice and we can swap the silicone for it. If you have modern sealant on a period surround and gaps where the frame meets the masonry, we can help, on sash and case windows, brick reveals and timber door frames alike.
London has a lot of flats and conversions, where windows are often on upper floors. Who looks after the outside of the frames can depend on the lease, so check that first, and access in Northwick Park is something to talk through when you book.
Whatever the size of the job, it’s backed by our 12-month guarantee in Northwick Park and across Greater London.
- Location
- Northwick Park (HA1, HA3, HA0)
- Wider area
- Greater London
- Cover
- 12 months on all our work
- Quotes
- A clear price before we start
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
What affects the cost of sand mastic
We quote each job individually. These are the things that affect it:
- The product the joint needs
- Any working-time requirements on site
- Any mould that needs treating
- Access and height
Every job is a little different, so each one gets its own quote. Size, access and the product the joint needs all play a part, and we will explain the quote if you ask.
What to tell us for a quote
Before you ask for a quote, have a think about:
- Roughly how big the job is
- Any access issues, like height or stairs
- What’s wrong with the joints now
- If someone has resealed it before
For a quote, ring 0345 464 0079 or email us with the location and a short description of the problem. We will send you a clear quote before any work starts.
Northwick Park homes and the weather
In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking. Historic houses like Headstone Manor (about 1.9 miles north-west) are a reminder that the area around Northwick Park has older buildings as well as new. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window.
If you let a flat or house near Kenton station, cracked sand mastic around sash windows lets in the draughts tenants complain about. Northwick Park is in London, so parking needs planning: let us know about parking bays, permits or a driveway. Managing a site like Harrow High School? Then its window and door frames need their mastic kept sound, just like a home’s.
Northwick Park is about 1 mile south-west of Kenton, in Greater London. Our applicators cover sand mastic for homeowners, landlords and businesses in Northwick Park and the surrounding area. Our Greater London coverage runs to 764 places, Northwick Park among them. There’s also a page for London, roughly 11 miles from Northwick Park.
Here we cover the HA1, HA3 and HA0 postcode area for sand mastic. If you need sand mastic at a property on Lyon Road, Manor Road and Gayton Road or a nearby road, we can help. Being close to the A404, Northwick Park is easy for our applicators to reach. Nearby, we also carry out sand mastic in Greenhill (1 mile north-west), Harrow on the Hill (1 mile south-west), South Kenton (1 mile east), Kenton (1 mile north-east) and Harrow (1 mile west). We also work in nearby towns such as London (11 miles south-east), City of Westminster (9 miles south-east), Marylebone (9 miles south-east), Kensington (7 miles south-east), St Pancras (10 miles east) and Shoreditch (11 miles east).
Near you in Northwick Park
Typical jobs here are in homes near St Anselm's Catholic Primary School, Orley Farm School and Preston Park. The nearest railway station is Kenton station, roughly 0.6 miles north-east of the centre. Other landmarks nearby include Northwick Park Hospital (less than half a mile north-east) and Kodak Museum (1.5 miles north-west). Open spaces near Northwick Park include Masons Field and Northala Fields.
What the job involves on each surface
Period and listed homes
On a listed home or in a conservation area, the right material matters. Sand mastic is often the preferred finish.
Brick reveals
Gaps between frame and brick let in rain and draughts. Renewing the mastic closes it.
What we do, step by step
On the day, we start by going over the job with you. We protect the surfaces around the joints before work begins. Most jobs take anything from a few hours to a full day, depending on how many windows. For a job in Northwick Park, parking and access are the things to plan: tell us about permits, visitor bays or off-street space, which floor we’re working on and whether there’s a lift.
- We check the window surrounds and agree which joints need renewing.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Deep voids are packed so the mastic is the right thickness.
- The mastic is mixed, pressed into the joint by hand and shaped.
- We dress the surface so it sits neatly against the masonry.
Preparing for the visit
- For indoor joints, keep the area dry beforehand if you can
- Keep children and pets away from the work area
- Mention if the joints have been sealed before
Ask for a quote
Every job is quoted individually, so start by telling us what you need. Simply call 0345 464 0079 or email us and describe the job, and photos are welcome.
Advice
Keeping the joints in good condition
Simple care keeps the joints in good condition. We recommend:
- Go gently near the mastic when preparing windows
- Leave the new mastic unpainted
- Have rotten timber repaired before new mastic goes in
- Find out about consent before window work on a listed home
Check the mastic when you check the paintwork. Small cracks are easier to deal with early.
Crumbling mastic lets rain into the joint. It can soak into the frame and the surrounding masonry so early renewal protects both.
Honest limits
Honest advice matters more to us than a booking, so here’s what new sealant won’t do:
- Sash cords, weights and draught-proofing of the sashes
- Damaged stone surrounds
- Putty and glazing repairs
If you are not sure, just ring 0345 464 0079 or drop us an email and we will give you a straight answer.
What we seal
- Period & listed homes
- Tenement windows
- Timber door frames
- Brick reveals
- Sash and case windows
- Stone surrounds
Also near Northwick Park
What else we do in Northwick Park
Why deal with it now?
An open joint round the frame lets weather in. Water can get to the frame and the masonry so renewing it early protects the window. In London conversions, one flat’s bathroom is often above another flat’s ceiling, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Putting it right early is much less trouble.
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether the work is at height. Your quote takes all of that into account.
Why Northwick Park customers choose us
- A 12-month guarantee on all work
- Fully insured
- Homes, businesses and hotels
- Rated 4.9 stars on Google
See how sealant jobs are priced and our reviews.
FAQs for Northwick Park
Can you help a landlord with a rental near Kenton station?
Yes, landlords and agents are among the people we work for. You can call 0345 464 0079 or email us with the details for a clear quote.
Is Northwick Park in your area for sand mastic?
Yes. Our work covers London and the South East, and Northwick Park is part of that. Just phone 0345 464 0079 or drop us an email with a few details of the job, and we will give you a clear quote.
Do I need permission for sand mastic on a listed building?
It’s best to ask your local planning authority first. Sand mastic is often favoured as like for like, but they decide.
Do you do commercial work?
Yes. Hotels, offices and other businesses use us, and we’re fully insured.
Do I have to be there?
We need access to the joints, so we will agree that with you when we book. Indoors, that generally means someone at home.
Can sand mastic be painted?
The usual advice is to leave sand mastic unpainted. Ask us before you decorate around it and we’ll advise.
Will the old sealant be removed?
Yes. Sealing over the old bead is the commonest cause of early failure, so we never do it.
Do the sealants smell?
It depends on the product. Some smell for a while, some hardly at all, and any smell fades as they cure.