Greater London · England
Sand Mastic in Finsbury
Sand mastic for Finsbury and the surrounding area: the right sealant, proper preparation and a neat finish. Ask us for a quick quote.
- Gaps between timber frames and stone or brick
- Crumbling sand mastic round a window
- Mastic that needs renewing before redecorating
FAQs for Finsbury
Is parking an issue for sand mastic in Finsbury?
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.
Can you help a landlord with a rental near Old Street station?
Yes, we work for letting agents and landlords. Just ring 0345 464 0079 or drop us an email and tell us about the property, and we will give you a clear price.
Are you fully insured?
Yes. Mr Mastic is fully insured, and we’ve been doing sealant work for more than 20 years.
What do you need from me for a quote?
Just the basics: where it is, what you’ve noticed and how we reach it. Then ring 0345 464 0079 or email us.
Does someone need to be in?
That depends on where the joints are. Inside work needs someone to give us access, and for outside work we will agree access with you when we book.
How long does sand mastic take?
That depends on the amount of work, but as a guide it takes a few hours for a single window, longer for several. We will give you a better idea when we quote.
Is it OK to seal over old sealant?
No, and we never do. It may look fine at first, but the new bead soon lifts. The old sealant has to come out completely.
Can I paint the new mastic?
Traditional guidance is not to paint over sand mastic. Ask us before you decorate around it and we’ll talk you through it.
Sand mastic in Finsbury
Our applicators renew the sand mastic around sash and case windows and doors set in stone or brick. Out comes the old, loose mastic, and new mastic is applied and shaped by hand. If you are dealing with mastic worn away on windows facing the weather and old cement repairs round a window that have failed, we can help, whatever the surface.
Much of London’s older housing was built with timber sash windows, some still in place and some long since replaced. Either way, the mastic between frame and brickwork is what stops draughts and rain getting in.
You are covered for a year from the day we finish. If anything isn’t right with it, call 0345 464 0079 or email us.
- Location
- Finsbury (EC1V, N1, EC2A)
- Region
- Greater London
- Cover
- A year, on every job
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
DIY sealant or a professional job?
If you are set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it doesn’t work out, we can still put it right.
If you’ve already had a go yourself, that is fine. We remove it and do the joint properly, so just mention it when you contact us.
Leave it or put it right?
Gaps round a sash window let in rain and draughts. 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, and a slow leak from a failed seal can end up in the flat below. Putting it right early is much less trouble.
A failed joint rarely gets cheaper to fix by waiting, as water and mould keep getting in. If you are not sure whether it needs doing, ring 0345 464 0079 or email us and we’ll give you an honest view and a quote.
Why choose Mr Mastic in Finsbury
- Approved under the ARBOMaster scheme
- We leave the area clean and tidy
- Anti-fungal silicone where joints get wet
- Trusted Arbo and Everbuild sealants
Take a look at how sealant jobs are priced or our reviews.
What sand mastic looks like in Finsbury
In a converted house or block, who looks after the windows depends on the lease, so check that before you book. Rainfall in the South East is lower than in much of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
If you look after a building such as Prior Weston Primary School and Children's Centre, the mastic around its windows and doors needs looking after like any other building’s. Homes close to Jewin Welsh Presbyterian Chapel include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Finsbury is about 2 miles north of London, in Greater London. Finsbury gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. Finsbury is one of 764 towns and villages in Greater London we cover.
Here we cover the EC1V, N1 and EC2A postcode area for sand mastic. Local streets include Oat Lane, Long Lane and Love Lane. Main roads around Finsbury include the A1 and A501. We also cover the places around Finsbury: St Luke's (1 mile north), Barbican Estate (1 mile south), City of London (1 mile south), Bishopsgate (1 mile south-east) and Shoreditch (1 mile east). Further out, we also cover City of Westminster (3 miles west), Kensington (5 miles west), Walthamstow (5 miles north-east), Hampstead (4 miles north-west), Ruislip (14 miles west) and Brompton (4 miles south-west).
Near you in Finsbury
Typical jobs here are in homes near Artillery Ground, Barts Health Archives and Charterhouse Square School. You’ll also find The Jugged Hare pub (less than half a mile south), St Mary-at-Hill (0.9 miles south-east) and Central Foundation Boys' School (under half a mile north-east). Finsbury has its own railway station: Old Street station. Nearby you’ll also find Honourable Artillery Company Museum (less than half a mile east) and Gabriel's Wharf (1.2 miles south-west). The countryside around Finsbury includes Barnsbury Wood and Ludgate Hill.
Towns and villages near Finsbury
What else we do in Finsbury
When it is not the sealant
We’ll always be straight with you, so here’s what new sealant will not do:
- Rotten sashes, sills or window boxes (a joiner’s job)
- Planning or listed building consent (your local planning authority decides)
- Masonry that needs repairing
If in doubt, ring 0345 464 0079 or drop us an email and we will say what we think before you book.
What we seal
- Sash and case windows
- Period & listed homes
- Stone surrounds
- Timber door frames
- Brick reveals
- Tenement windows
Do you need sand mastic in Finsbury?
Timber swells and shrinks with the weather. The movement cracks the mastic little by little.
It’s worth asking for a quote if you see:
- Mastic worn away on windows facing the weather
- Crumbling sand mastic round a window
- Cement or filler used on old window joints that has cracked
- Wind and rain getting in round a sash window
Finsbury is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Before you book anyone
- Who does the work, and how experienced they are
- Whether you can choose the colour
- Whether the sealant suits the joint
- What happens if they find a problem under the old sealant
Surface by surface
Brick reveals
Sand mastic is also used where timber frames meet brick. It suits older brickwork.
Timber door frames
Door frames get knocked and soaked and the mastic can crack early. We rake it out and renew it.
How it works
The work is kept neat and contained to the area we’re working on. Expect the work to take a few hours per window, depending on the condition of the joints. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Finsbury. It helps if you can point us to a visitor permit or a bay close to the door.
- We start by checking each surround and agreeing the joints to renew.
- Old, loose mastic is raked out and the joint cleaned.
- We pack any deep gaps so the mastic sits at the right depth.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The mastic is finished to sit tidily against the stone or brick.
How to prepare
- Tell us about any previous sealing or DIY attempts
- Clear items away from the joints we are working on
- For business premises, tell us about site rules or sign-in
Ask for a quote
We don’t publish a price list, as no two jobs are quite the same. Instead, we give you a clear price for your job. To get started, phone 0345 464 0079 or send us an email.
Advice
Landlords, agents and businesses in Finsbury
From a single let to a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
Letting agents often deal with us directly. Tell us the address, the job and how access works and we will quote.