Greater London · England
Sand Mastic in Brentford
Sand mastic in Brentford from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Gaps where the frame meets the masonry
- Modern sealant on a period surround
- Patchy fillers round a sash window
The process
On the day, there’s very little for you to do. Show us the job and we’ll take it from there. The job generally takes a few hours per window, depending on the condition of the joints, including the tidy-up. In Brentford, flats, stairs and shared entrances are part of the routine. If the building has a concierge, managing agent or access rules, tell us when you book.
- We check the window surrounds and agree which joints need renewing.
- We rake out the old mastic and clean the joint.
- 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.
How to prepare
- Mention if the joints have been sealed before
- Tell us if parking is tricky
- Let us know if you’ve seen damp or leaks
Getting a quote
Want a quote for sand mastic? Please phone 0345 464 0079 or email us and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.
Related advice
About our sand mastic in Brentford
Silicone on a period window often looks wrong and doesn’t suit the building. Sand mastic gives a finish that matches the age of the house and we can swap the silicone for it. If you have gaps between timber frames and stone or brick and silicone on a period window that looks wrong, we can help.
London has a lot of flats and conversions, where windows are often on upper floors. In a converted house or block, the lease generally says who is responsible for the windows, so it’s worth checking before booking, and access in Brentford is something to talk through when you book.
Every job comes with our one-year guarantee.
- Place
- Brentford (TW8, W3, W4, W5)
- Region
- Greater London
- Guarantee
- A year, on every job
- Price
- A clear quote up front
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Signs you need sand mastic in Brentford
Shallow joints are a common cause. Mastic that’s too thin cracks and drops out, which is why we pack deep voids first and get the depth right.
Any of these means the joints need attention:
- Tired mastic found when preparing windows for paint
- Gaps between timber frames and stone or brick
- Silicone on a period window that looks wrong
- Patchy fillers round a sash window
As a London address, Brentford can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
What to look for in a quote
- What insurance they hold
- What happens if the job turns out different
- How the joint is cleaned and prepared
- What the cure time is
What happens if it’s left?
Not every filler suits an old window surround. Sand mastic is the like-for-like choice, which can matter on listed and conservation-area homes. Converted houses in London often have a bathroom above someone else’s living room, and a slow leak from a failed seal can end up in the flat below. Putting it right early is much less trouble for homes in Brentford.
A few things move the cost up or down: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether we need extra access for height. We take all of that into account in your quote.
Why us?
- 180+ five-star Google reviews
- Every job guaranteed for a year
- Old sealant always removed completely
- Fully insured
How we quote for sand mastic
For a quick quote, just ask. The main things that affect it are:
- How many areas need sealing
- How much there is to do
- Any working-time requirements on site
- How much old sealant there is and how hard it is to remove
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.
What to tell us for a quote
A few details help us give you an accurate quote. When you ask for a quote, tell us:
- The type of property
- Where the property is
- A few pictures by email, if you can
- What’s wrong with the joints now
Getting a quote is simple: tell us what needs doing and where, and roughly how big it is. A few pictures by email make the job easier to understand, and we will take it from there.
Keeping the joints in good condition
After the cure time, these simple habits help:
- Keep sills and gutters clear so water drains away
- Inspect the joints round the windows every year or so
- Do not paint over the new mastic
- Renew mastic before redecorating the windows
When preparing windows for paint, take care around the mastic. It can be damaged by heavy scraping.
Fine cracks show the mastic is starting to fail. It’s easier to renew it before it drops out.
Brentford 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 Kew Palace (about 0.5 miles south-east) are a reminder that the area around Brentford has older buildings as well as new. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window.
For site and facilities teams at buildings such as St Paul's CofE Primary School, the mastic around its windows and doors needs looking after like any other building’s. Rented homes near Brentford station change hands often, and cracked sand mastic around sash windows lets in the draughts tenants complain about.
Brentford is about 2 miles south of Ealing, in Greater London. If you need sand mastic in Brentford, it’s easy to get a quote: please ring 0345 464 0079 or email us. We’re based in Crawley and cover Greater London. We cover 764 towns and villages across Greater London, from the larger towns to small villages. You can also see our page for London, about 9 miles away.
All of TW8, W3, W4 and W5 is within our area for sand mastic. If you need sand mastic at a property on High Street, Market Place and New Road or anywhere close by, we can help. You will find Brentford on the A4 and A315, which makes it straightforward to reach with everything needed for sand mastic. If you’re just outside Brentford, we cover Brentford End (1 mile south-west), Northfields (1 mile north-west), Gillette Corner (1 mile west), Isleworth (2 miles south-west) and Spring Grove (2 miles west). Further out, we also cover London (9 miles east), City of Westminster (7 miles east), Marylebone (7 miles east), Kensington (4 miles east), St Pancras (8 miles east) and Shoreditch (10 miles east).
Local landmarks in Brentford
Locally, jobs take us to homes and businesses close to Library for Iranian Studies, Brentford School for Girls and Kew College Prep. Nearby too are The Brook pub (within half a mile south-west) and Kew Green (0.7 miles south-east). There’s a railway station in Brentford itself: Brentford station. Other landmarks nearby include Treaty Centre (3 miles south-west) and Musical Museum (0.5 miles east). The countryside around Brentford includes Kew Gardens Lake and Long Wood.
Can I do it myself?
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.
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Common questions in Brentford
Can parking be tricky for a visit in Brentford?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. The visit is then planned around what’s available.
Do you work for landlords with property near Brentford station?
Yes, rental work is part of what we do. Just call 0345 464 0079 or send us an email and tell us about the property, and we will give you a clear price.
What does sand mastic cost?
It depends on the job, so we quote each one individually. To get one, ring 0345 464 0079 or drop us an email with a short description of the job.
Do you come to Brentford?
We do. Brentford is part of the area we cover.
Should I try DIY first?
That depends on the joint. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional, while a short indoor joint may be within reach.
Is it messy?
No. We protect the surfaces around the joints, and we tidy up before we go.
Can new sealant go over the old?
No. We remove every bit of old sealant first, so the new sealant bonds properly.
Is sand mastic better than silicone for my windows?
It depends on the window. On many period windows, sand mastic looks right and suits the building and newer frames generally get a flexible sealant.
Towns and villages near Brentford
What else we do in Brentford
When something else is needed
A few problems are outside what sealant work can do:
- Whether work needs listed building consent
- Sashes that need overhauling
- Crumbling stone or brickwork round the window
If you are not sure, just phone 0345 464 0079 or email us and we will give you a straight answer before you book.
What we seal
- Sash and case windows
- Stone surrounds
- Period & listed homes
- Tenement windows
- Timber door frames
- Brick reveals