Greater London · England
Sand mastic for sash & case windows in Crouch End, Greater London
Sand mastic for Crouch End and the surrounding area: careful preparation, the right product and tidy work. Ask us for a quick quote.
- Gaps round a timber door in stone or brick
- Wind and rain getting in round a sash window
- Mastic that needs renewing before redecorating
About our sand mastic in Crouch End
A silicone bead around a sash window can look out of place and doesn’t suit the building. Sand mastic gives a finish that matches the age of the house, and we can replace one with the other. Common call-outs are for mastic round period door frames that has failed and mastic worn away on windows facing the weather, across timber door frames, period & listed homes and stone surrounds.
From mansion-block windows to modern glazing in new flats, London has every kind of frame. The mastic around them dries out and cracks with age, letting in draughts and water.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we will put it right.
- Location
- Crouch End (N8, N19, N4)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
DIY sealant or a professional job?
Sealing over old silicone is the commonest DIY error. New silicone won’t bond to old, so it peels away and traps moisture behind it. Everything old must be removed first.
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
Sand mastic in Crouch End: local notes
In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking. London and the South East are among the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
As a London address, Crouch End can be tricky for parking: tell us about permits, visitor bays or off-street space when you book. For site and facilities teams at buildings such as Rokesly Infant & Nursery School, the mastic around its windows and doors needs looking after like any other building’s. If you live in an older home near Christ Church, the joint between an old wall and a newer frame is usually the first place rain gets in.
Crouch End is about 2 miles north-west of Highbury, in Greater London. Across the N8 area, we cover sand mastic for homes and businesses. Crouch End is one of 764 places in Greater London we cover for sand mastic. Our London page covers work nearby, about 6 miles away.
Here we cover the N8, N19 and N4 postcode area for sand mastic. If you need sand mastic at a property on New Road, Park Road and Ella Road or anywhere close by, our applicators can take on the job. If you are just outside Crouch End, we cover Hornsey (1 mile north-east), Stroud Green (1 mile east), Turnpike Lane (1 mile north-east), Highgate (1 mile south-west) and Upper Holloway (1 mile south). We also work in nearby towns such as London (6 miles south), City of Westminster (5 miles south), Marylebone (4 miles south), Kensington (6 miles south-west), St Pancras (4 miles south) and Shoreditch (4 miles south-east).
Landmarks near Crouch End
In Crouch End, that means homes and buildings near Asanté Academy of Chinese Medicine, Hornsey School for Girls and Queens pub, among other places. The nearest railway station is Crouch Hill station, about 0.7 miles south-east of the centre. A little further out are Montfichet's Tower (4.7 miles south) and Hornsey Central Hospital (within half a mile north-west). For a walk, there’s Parkland Walk and Darland's Lake.
Looking after it afterwards
Good habits help new joints last longer. Our tips:
- Go gently near the mastic when preparing windows
- Get any rot dealt with first
- Keep sills and gutters clear so water drains away
- Ask the planning authority about consent for listed or conservation-area homes
Avoid painting over the new mastic, which is the traditional advice. If you’re redecorating, ask us first.
Good mastic helps keep the frame dry. Failed mastic lets water reach the timber and timber that stays wet can rot.
Different surfaces, different methods
Stone surrounds
Old stone surrounds are often uneven, so the gap isn’t the same all the way round. Sand mastic is shaped by hand to suit.
Timber door frames
Doors face weather and wear, so their mastic can fail sooner. It’s renewed by hand.
What affects the quote in Crouch End
We quote each job individually. This is what makes a difference:
- How many areas need sealing
- How easy the joints are to reach
- The size of the job
- Which sealant suits the joint
Some things make a job bigger or smaller: the old material and how easily it comes out, whether mould needs treating, and whether the work is at height. We take all of that into account in your quote.
What to tell us for a quote
To make quoting easier, let us know:
- Any previous sealing or DIY work
- A few photos by email, if you can
- Access, such as stairs, a lift or height
- Where the property is
Getting a quote is simple: tell us what needs doing and where and its rough size. Photos by email help us understand the job, and we’ll take it from there.
Leave it or put it right?
Gaps round a sash window let in rain and draughts. Left, water can reach the timber and the wall, so dealing with it now protects both. In London conversions, one flat’s bathroom is often above another flat’s ceiling, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler for homes in Crouch End.
Instead of a standard rate, we look at what your job involves: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
Why us?
- Full insurance on every job
- Over 20 years’ experience
- Any old sealant cut out fully, not covered over
- Rated 4.9 stars on Google
Read what affects the cost or customer reviews.
Also near Crouch End
More services for Crouch End
The process
We work through the job in order: protection first, then preparation, sealing and a tidy-up. For most jobs that takes a few hours per window, depending on the condition of the joints and we leave things clean and tidy. In a London area like Crouch End, the main things to plan are parking and access: let us know about parking, the floor we’ll be working on and any lift or shared entrance.
- First we agree which joints need doing.
- Old mastic and any loose material are raked out.
- Deep gaps are packed so the mastic sits at the right depth.
- The sand mastic is mixed and pressed into the joint by hand.
- We dress the finish so it sits neatly against the masonry.
Before we arrive
- Plan for the work area to be out of bounds to pets and children
- Let us know if you’ve seen damp or leaks
- Let us know about earlier repairs to the joints
Ask for a quote
There’s no standard price list. Instead, your job gets its own clear quote. To get started, call 0345 464 0079 or drop us an email.
Advice
FAQs for Crouch End
Is Crouch End in your area for sand mastic?
Yes. We work across London and the South East, and Crouch End is part of that. You can phone 0345 464 0079 or send us an email and tell us what needs doing, and we will send you a clear quote.
Can parking be tricky for a visit in Crouch End?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. That way the visit can be planned around it.
Should I try DIY first?
It depends on the job. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional.
What do you put in the joint?
The product depends on the job: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. Brands we use include Arbo and Everbuild.
What information do you need?
The location, the problem and the rough size of the job. If you can, email a few pictures.
Will you leave a mess?
No. We protect the surfaces around the joints, and we tidy up before we go.
How long does sand mastic take?
It depends on the size of the job, but most jobs take a few hours for a single window, longer for several. We will tell you when we quote.
Can you match the sealant colour?
Yes. Sealants come in white, clear, grey and other colours, and we will agree it with you first.
For landlords and businesses
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements and we will quote.