Hertfordshire · England
Window Mastic in The Flints
Window mastic across The Flints and nearby, with old sealant always removed completely and a 12-month guarantee.
- Hard, cracked sealant around windows
- Draughty joints inside around the window
- Rushed sealant from a window installation
What affects the quote in The Flints
We quote each job individually. These are the things that affect it:
- How many areas need sealing
- The product the joint needs
- Working hours on commercial sites
- How much there is to do
Leaving a failed joint generally makes the job bigger, not smaller, as water and mould keep getting in. If you’re not sure whether it needs doing, call 0345 464 0079 or send us an email and we will give you an honest view and a quote.
Asking for a quote
When you call or email, it’s useful to know:
- The rough size of the job
- If it’s domestic, commercial or a hotel
- Access, such as stairs, a lift or height
- Where the property is
For window mastic in The Flints, call 0345 464 0079 or drop us an email. A short description of the job and where it is helps us quote, and you’ll get a clear quote before any work starts.
About our window mastic in The Flints
If you can feel air around a shut window, the gap is often at the frame. Resealing that joint can make a room feel noticeably less draughty. Where the air is getting in through the window itself, we’ll say so. If you have cracked sealant at the sill ends and a bead that doesn’t match the frame, we can put it right.
Somewhere as small as The Flints, older homes often have timber frames set in stone or brickwork. Not every older frame suits a modern silicone bead, so the sealant has to be chosen to suit the building.
All our work comes with our 12-month guarantee.
- Where
- The Flints (SG5)
- Wider area
- Hertfordshire
- Cover
- 12 months on all our work
- Price
- A clear price before any work starts
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
What happens on the day
We bring everything the job needs with us, so you do not need to buy or prepare anything. Once we have agreed what’s being done, the area is protected and the work begins. Most jobs take a morning for a couple of windows and a door. Somewhere as small as The Flints, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- First, we go round the frames with you and agree the list.
- We remove the old mastic and clean the frame edge and wall.
- Where the gap is deep, backing rod goes in first.
- A flexible exterior sealant is applied in a colour to suit the frame.
- Every joint is tooled smooth and checked before we leave.
Getting ready for the visit
- Keep children and pets away from the work area
- Clear the area around the work
- Mention any leaks or damp you’ve noticed
Get a quote
The more we know about the job, the more useful the quote. Let us know the location, the problem and roughly how many joints, and email photos if that is easy.
Read more
What window mastic looks like in The Flints
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.
Managing a site like Offley Endowed Primary School? Then larger buildings have plenty of frames, and the mastic around each one ages. For an older house near a landmark such as Church of St Mary Magdalene, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
The Flints is about 4 miles south-west of Hitchin, in Hertfordshire. We carry out window mastic for homes and businesses in The Flints. The Flints is one of 381 places in Hertfordshire we cover for window mastic. Our London page covers work nearby, about 32 miles away.
All of SG5 is within our area for window mastic. Nearby, we also carry out window mastic in Great Offley (1 mile east), Temple End (2 miles east) and Ley Green (2 miles south-east). Larger places within reach include Hemel Hempstead (13 miles south), Stevenage (7 miles east), St Albans (12 miles south), Welwyn Garden City (11 miles south-east), Harpenden (8 miles south) and Hitchin (4 miles north-east).
Around The Flints
We work in homes and buildings around The Bull Public House. The closest station to The Flints is Luton station, about 4.1 miles south-west of the centre. A little further out are Ravensburgh Castle (2.7 miles north-west) and John Dony Field Centre (2.9 miles south-west). Green spaces nearby include Markham's Hill and Pegsdon Hills.
Also near The Flints
Also in The Flints
Different surfaces, different methods
Composite doors
If the door itself is draughty, the issue may be the door seals or hinges rather than the frame mastic. We seal the frame and let you know about anything else.
Aluminium frames
Large aluminium doors have long joints down each side and across the head, and the threshold joint takes a lot of water. Each is cleaned, backed where deep and resealed.
DIY sealant or a professional job?
If you do try it yourself, take your time over the preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
Landlord and commercial work in The Flints
Failed sealant is one of the commonest items on a check-out report, and it’s quick to put right between tenancies. Several properties can be quoted together.
Housing providers, facilities teams and property managers book us too. We can quote a run of properties together.
How to look after the new joints
Good habits help new joints last longer. A few tips:
- Repaint timber before it’s bare
- Keep drainage slots and sill grooves clear
- Do not use solvent cleaners on the joint
- Keep jet washers away from the mastic
On timber frames, keep the paintwork in good order, because bare, wet timber moves more and pulls at the joint. Keep paint off the silicone itself.
A failed joint lets water into the wall a little at a time. Often the first sign is a damp patch inside or flaking paint on the reveal. Early resealing stops it reaching that point.
Common problems we fix in The Flints
Joints that are too thin or too deep fail early. A thin smear across a wide gap has nothing to it, while a joint packed solid cannot stretch. That is what backing rod is for.
Any of these means the joints need attention:
- Draughts coming in around windows and doors
- Gaps left after new windows were fitted
- Cracked internal joints between frame and plaster
- Sealant in the wrong colour for the frame
Rented homes near Luton station change hands often, and renewing tired window mastic between tenants heads off draught and damp complaints.
Comparing quotes
- Whether VAT is included
- Whether they seal over old material or remove it
- What happens if they find a problem under the old sealant
- Who does the work, and how experienced they are
The Flints: your questions answered
Will you come out to The Flints?
Yes, smaller places are covered as well as towns. We work across London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Can you help a landlord with a rental near Luton station?
Yes. We work for letting agents and landlords as well as householders, and several properties can go on one quote. Just call 0345 464 0079 or email us with the address and what needs doing, and we’ll give you a clear quote.
Are you an approved applicator?
Yes. We are an ARBOMaster approved applicator, the approved applicator scheme for Arbo sealants.
Is the work guaranteed?
Yes. Every job comes with our 12-month guarantee, and we’re fully insured.
Where is Mr Mastic based?
Our base is Crawley, with over 20 years’ experience. Our area covers South East England, London and Scotland.
Do you work for hotels and businesses?
Yes. We have worked for hotels, offices and other businesses.
Can you do upstairs windows?
Yes, where it’s safe. Higher or awkward frames may need extra access, and we’ll confirm what’s needed.
Can you seal the gap between the frame and the plaster indoors?
Yes. Plenty of draughts come through the inside joint as well as the outside, so it can be worth sealing both.