Greater London · England
Window & door mastic in Downham, Greater London
Window mastic for Downham, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Old mastic that has gone black or come away
- Untidy mastic left by window fitters
- White mastic on grey or black frames
Window mastic in Downham
The new joint does not 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. Typical jobs include water coming in at the bottom corners of a door and hard, cracked sealant around windows, on patio & French doors, window sills and aluminium frames.
London has a lot of flats and conversions, where windows are often on upper floors. In a converted house or block, the lease usually says who is responsible for the windows, so it’s worth checking before booking.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we’ll put it right.
- Location
- Downham (BR1, SE6, SE12)
- Region
- Greater London
- Guarantee
- A year, on every job
- Price
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Downham homes and the weather
With historic houses such as Bromley Palace (about 1.7 miles south-east) nearby, there’s older building stock in the area around Downham as well as newer homes. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window. In London conversions and blocks, the lease decides who is responsible for the frames, so check that before booking.
Downham is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book. For site and facilities teams at buildings such as Rangefield Primary School, its window and door frames need their mastic kept sound, just like a home’s. If you live in an older home near St Barnabas, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Downham is about 2 miles north of Bromley, in Greater London. If you need window mastic in Downham, please call 0345 464 0079 or send us an email for a quick quote. We cover Greater London from our Crawley base. Downham is one of 764 towns and villages in Greater London we cover. You can also see our page for London, about 7 miles away.
All of BR1, SE6 and SE12 is covered for window mastic. Whether your property is on Shaw Road, Arcus Road and Brook Lane or a nearby road, we can help. We also cover the places around Downham: Plaistow (1 mile south), Grove Park (1 mile north-east), Sundridge (1 mile south-east), Chinbrook (1 mile east) and Bellingham (1 mile west). Within a short drive, we also cover London (7 miles north-west), City of Westminster (9 miles north-west), Marylebone (9 miles north-west), Kensington (10 miles north-west), St Pancras (9 miles north-west) and Shoreditch (8 miles north-west).
Landmarks near Downham
Around Downham, our work takes us to homes and buildings near Holy Trinity College Bromley, Downham Fields and Bonus Pastor Catholic College, among other places. For rail, the closest station is Grove Park station, about 0.8 miles north-east of the centre. Nearby you will also find The Glades (1.6 miles south) and Greenwich Castle (3.6 miles north). Green spaces nearby include Summer Hill and Downham Woodland Walk.
Different surfaces, different methods
Timber windows & doors
Timber moves with moisture as well as heat, so a flexible sealant is essential. We seal onto sound, dry paintwork or timber.
Window sills
Masonry sills can have joints where water gets in, including the one between the sill and the frame above. Those are sealed with a product suited to stone or concrete.
Quotes for window mastic in Downham
We don’t publish a price list. The quote depends on:
- Access and height
- How many areas need sealing
- How much there is to do
- When we can work, for business premises
Doing several joints on one visit normally makes better use of the time than several visits, so it’s worth mentioning everything you’d like done. We’ll give you a clear price for the lot.
What we need to know
When you call or email, it’s useful to know:
- Roughly how big the job is
- Whether it has been sealed before
- Access, such as stairs, a lift or height
- Where the property is
A good description makes for an accurate quote. Tell us where the job is, what’s wrong and how much there is, and email pictures if that’s easy.
DIY versus a professional finish
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
If you do try it yourself, take your time over the preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it doesn’t work out, we can still put it right.
When it is not the sealant
In fairness, there are a few things sealant will not fix:
- Penetrating damp from a failed cavity tray or render
- Faulty window hardware
- A door that needs adjusting, rehanging or new seals
If in doubt, call 0345 464 0079 or email us and we’ll say what we think.
What we seal
- uPVC windows
- Timber windows & doors
- Patio & French doors
- Window sills
- Composite doors
- Aluminium frames
Also near Downham
More services for Downham
Why it’s worth doing now in Downham
The work is quick compared with the damage it prevents: the visit takes a few hours for a handful of frames, longer for a whole house. Leave it until water is coming in and you may need plastering and decorating as well. 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. Dealing with it early is far simpler.
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed. Call for a quick quote and we’ll explain what it covers.
Why book with us
- An ARBOMaster approved applicator
- Quality sealants from Arbo and Everbuild
- Every job guaranteed for a year
- We leave the area clean and tidy
Landlords, agents and businesses in Downham
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements.
Hotels need rooms back in use, so the work can be planned room by room. We have worked in hotels as well as homes and businesses.
Common questions in Downham
Can you help a landlord with a rental near Grove Park 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 Downham in your area for window mastic?
Yes, Downham is within the area we cover. We work across London and the South East. Just phone 0345 464 0079 or drop us an email with a few details of the job.
Will resealing my frames help with draughts?
In many cases. The gap between frame and wall is a common source of draughts, and resealing inside and out closes it.
How much does window mastic cost in Downham?
Size, access and the old material all affect the cost. Call for a quick quote.
Where is Mr Mastic based?
We work from Crawley. Our applicators cover Downham.
Do you work for hotels and businesses?
Yes. Hotels, offices and other businesses use us, and we’re fully insured.
Do you have insurance?
Yes. We’re fully insured, and we have been doing sealant work for more than 20 years.
Will the old sealant be removed?
Yes. We cut out all the old sealant and clean the joint.
The process
The work is kept neat and contained to the joints we are treating, so you can get on with your day. The job generally takes a morning for a couple of windows and a door, and we tell you how long to leave it before we go. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. If the building has a concierge, managing agent or access rules, tell us when you book.
- First, we confirm safe access to each frame.
- Old, cracked mastic is removed completely, along with any loose debris.
- The surfaces are cleaned and left dry, and primed where the sealant calls for it.
- Backing rod fills deep voids and the sealant goes in on top.
- The joint is shaped to shed water and the area tidied.
Getting ready for the visit
- Tell us if parking is tricky
- Keep pets and children clear of the area while we work
- Let us know if you’ve seen damp or leaks
Getting a quote
Asking for a quote is easy: let us know the job and the location and its rough size. A few pictures by email make the job easier to understand.