Greater London · England
Sidcup Window Mastic
Window and door frames in Sidcup need attention? We cut out the old, prepare the joints and apply the right sealant, with a 12-month guarantee.
- Draughty joints inside around the window
- Gaps where the sill meets the wall
- Sealant in the wrong colour for the frame
Sidcup homes and the weather
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. With historic houses such as Danson House (about 1.7 miles north) nearby, there’s older building stock in the area around Sidcup as well as newer homes. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic.
Managing a site like Birkbeck Primary School? Then its window and door frames need their mastic kept sound, just like a home’s. As a London address, Sidcup can be tricky for parking: let us know about parking bays, permits or a driveway.
Sidcup is about 3 miles north of Orpington, in Greater London. Every kind of property in Sidcup can book us for window mastic. Every job comes with our 12-month guarantee. Across Greater London, we cover 764 places, and Sidcup is one of them. You can also see our page for London, roughly 10 miles from Sidcup.
We cover every part of the DA14, DA15, SE9 and DA5 postcode area for window mastic. That includes homes and businesses on Station Road, High Street and Jubilee Way. Being close to the A211 and A2001, Sidcup is simple for us to get to for window mastic. Nearby, we also carry out window mastic in Albany Park (1 mile south), Blendon (1 mile north-east), Foots Cray (1 mile south-east), Bexley (2 miles north-east) and North Cray (2 miles east). We also work in nearby towns such as London (10 miles north-west), City of Westminster (12 miles north-west), Marylebone (12 miles north-west), Kensington (14 miles west), St Pancras (11 miles north-west) and Shoreditch (10 miles north-west).
Around Sidcup
Typical jobs here are in homes near The Alma pub, Waring Park and Chislehurst and Sidcup Grammar School, among other places. There’s a railway station in Sidcup itself: Sidcup station. Well-known places in the area include Queen Mary's Hospital (1 mile south) and Broadway Shopping Centre (2.4 miles north-east). For a walk, there’s Summer Hill and The Tarn.
About our window mastic in Sidcup
The new joint doesn’t have to be white. We can seal in white, brown, anthracite grey, black or clear, so the line suits the frame instead of standing out. Common call-outs are for water coming in at the bottom corners of a door and gaps between the frame and the inside reveal, across window sills, aluminium frames and patio & French doors.
London homes have every kind of window, from timber sashes in period terraces to aluminium and uPVC in newer blocks. Over the years, the sealant around them shrinks, cracks and pulls away, letting in draughts and water.
All of our work is guaranteed for twelve months, and the guarantee is the same wherever you are.
- Place
- Sidcup (DA14, DA15, SE9, DA5)
- Wider area
- Greater London
- Cover
- 12 months on all our work
- Price
- A clear price before work begins
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Why deal with it now?
The work is quick compared with the damage it prevents: the visit takes a morning for a couple of windows and a door. Wait for damp to appear and there may be plaster and decorating to sort out too. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and once it shows in Sidcup, the repair is bigger than a sealant job.
The cost reflects the work involved, not guesswork. That’s why we ask about the job first and give you a clear quote before any work starts.
Why choose Mr Mastic in Sidcup
- Anti-fungal sanitary silicone in wet areas
- We agree the colour with you first
- Full insurance on every job
- Neat joints and a tidy finish
Take a look at our cost guide and our reviews.
Work for landlords, hotels and businesses
Businesses can book us for washrooms, kitchens, offices and more. For commercial premises, we can talk through working times when we quote.
If you manage several properties in or around Sidcup, several properties can be quoted together. Send us the addresses and the work at each.
How the job changes by surface
Patio & French doors
Door frames take knocks and movement every time the doors are used. The sealant must cope with it.
uPVC windows
uPVC expands and contracts noticeably with temperature, so the joint needs a low-modulus sealant that stays flexible. We match white, brown, anthracite grey and black frames.
FAQs for Sidcup
Can you help a landlord with a rental near Sidcup station?
Yes, landlords and agents are among the people we work for. Just ring 0345 464 0079 or email us with the address and what needs doing, and we’ll send you a clear quote.
Is Sidcup in your area for window mastic?
Yes. We work across London and the South East, and Sidcup is part of that. Just ring 0345 464 0079 or drop us an email with a few details of the job.
How long does it take to reseal the windows on a house?
A handful of frames is a short visit, while a whole house takes longer. You’ll get a timescale with the quote.
Does the work come with a guarantee?
Yes. Each job is covered for 12 months.
Will the old sealant be removed?
Yes, every time. New sealant will not bond properly to old, so the joint is cleaned back first.
Can you seal over the old sealant?
No, and we never do. It can look neat for a few weeks, but the new bead soon lifts. The old sealant has to come out completely.
Will you leave a mess?
Very little: the area around the joints is protected first, and we clear up the old sealant and our materials before we leave.
Do you do commercial work?
Yes. Larger jobs can be planned room by room or area by area to suit the site.
Should I try it myself first?
A DIY attempt doesn’t rule out a professional job. We cut it out and start again, so tell us about it when you ask for a quote.
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it lifts and traps water and mould underneath. All the old material has to come out first.
Nearby places to Sidcup
More services for Sidcup
Signs you need window mastic in Sidcup
Timber windows bring their own problems. Old mastic gets painted over and cracks under the paint, and the wood moves with damp as well as heat.
The problems people usually mention when they call are:
- Untidy mastic left by window fitters
- Cracked internal joints between frame and plaster
- Damp patches on the reveal after heavy rain
- Hard, cracked sealant around windows
For landlords with property near Sidcup station, renewing tired window mastic between tenants heads off draught and damp complaints.
Before you book anyone
- Which colour the sealant will be
- How long the guarantee is
- Whether VAT is included
- How hidden problems are handled
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 work itself takes a few hours for a handful of frames, longer for a whole house, including the tidy-up. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Sidcup. It helps if you can point us to a visitor permit or a bay close to the door.
- First, we confirm safe access to each frame.
- All the failed sealant is cut away.
- Frame and wall are cleaned and must be dry before sealing.
- Backing rod fills deep voids and the sealant goes in on top.
- The joint is shaped to shed water and the area tidied.
Preparing for the visit
- Mention any leaks or damp you’ve noticed
- Tell us about any previous sealing or DIY attempts
- Move anything stored near the joints
Ask for a quote
There’s no standard price list, as no two jobs are quite the same. Instead, we give you a clear quote for your job. To get started, call 0345 464 0079 or send us an email.
Related advice
When something else is needed
Before you book, it’s worth knowing the limits:
- Condensation trapped between the panes
- Faulty window hardware
- Soft or decayed wood in the frame
If in doubt, phone 0345 464 0079 or send us an email and we will say what we think before you book.
Joints and surfaces we work on
- Composite doors
- uPVC windows
- Timber windows & doors
- Patio & French doors
- Aluminium frames
- Window sills