Hertfordshire · England
External Mastic in Great Amwell
Our applicators work in Great Amwell on sealing brickwork movement joints, render, cladding and façade joints. Old sealant removed completely, joints prepared properly and every job guaranteed for a year.
- Panel joints letting water in
- Failed seals between different materials
- Rain getting behind render or cladding at a joint
External mastic in Great Amwell, done properly
On houses, flats and commercial buildings across Great Amwell, we reseal joints in brickwork, render, cladding and façade panels. The preparation is the same whatever the wall: clean joint faces and the right depth. Common call-outs are for joints where the bead has come unstuck and panel joints letting water in, on joints between brick and frames, façade panels and render & cladding joints.
Older homes in small places like Great Amwell may be stone, brick or timber-framed, often with later extensions. Where one material meets another is where water generally gets in.
Our work is backed for twelve months, in Great Amwell and everywhere else we cover.
- Location
- Great Amwell (SG12)
- Region
- Hertfordshire
- Cover
- A year, on every job
- Quote
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
How the visit works
We bring everything the job needs with us, so there’s nothing for you to buy. Once we have agreed what’s being done, the area is protected and the work begins. It normally takes a few hours for a handful of joints, longer for a whole elevation. Somewhere like Great Amwell needs a little journey planning: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- First we look over the joints with you, agree which to renew and talk through access.
- The old mastic and anything lodged in the joint is removed.
- We clean both faces of the joint and prime them where the product calls for it.
- We push in closed-cell backing rod so the sealant is the right depth and bonds to the sides only.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
Before we arrive
- Mention any leaks or damp you’ve noticed
- Mention any tricky access
- Plan for the work area to be out of bounds to pets and children
Getting a quote
The more we know about the job, the more useful the quote. Tell us where the job is, what’s wrong and how much there is.
Related advice
Surface by surface
Brickwork movement joints
Brick moves with heat and moisture, and grows a little over time. That movement goes into the joint, so the sealant in it must stay soft and stretchy.
Joints between dissimilar materials
Each side of the joint may need its own preparation. Both surfaces are cleaned and primed as the product requires.
Great Amwell buildings and the weather
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.
For site and facilities teams at buildings such as Presdales School, its movement joints, gutters and trims need looking after like any other building’s. If you live in an older home near Parish Church of St John the Baptist, old and new materials meet at the roofline and walls, which is where sealant earns its keep. Letting a property close to St Margarets (Herts) station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Great Amwell is about 1 mile south-east of Ware, in Hertfordshire. We provide external mastic to homes and businesses in Great Amwell and nearby. Our area takes in 381 places across Hertfordshire. You can also see our page for London, about 21 miles away.
Jobs for external mastic in SG12 is quoted and booked the same way as anywhere else. Local streets include Church Path, Amwell Hill and Madgeways Lane, all of which we cover. We also cover the places around Great Amwell: St Margarets (1 mile south-east), Hailey (1 mile south), Little Amwell (1 mile south-west), Rush Green (1 mile west) and Stanstead Abbotts (1 mile south-east). Further out, we also cover Stevenage (11 miles north-west), St Albans (14 miles west), Bishop's Stortford (9 miles north-east), Welwyn Garden City (8 miles west), Harpenden (14 miles west) and Hitchin (15 miles north-west).
Landmarks near Great Amwell
Locally, jobs take us to homes and businesses close to Hertford Regional College and Jolly Fisherman Public House. Great Amwell’s nearest station is St Margarets (Herts) station, about 0.9 miles south-east of the centre. Other landmarks nearby include Museum of Street Lighting (less than half a mile north) and Barrowfield (1.4 miles west). Not far away are Amwell Quarry.
What affects the quote in Great Amwell
The price is agreed before any work begins. It takes into account:
- How easy the joints are to reach
- The number of rooms or windows
- Any working-time requirements on site
- How much old sealant there is and how hard it is to remove
A failed joint rarely gets cheaper to fix by waiting, as water and mould keep getting in. If you’re unsure, ring 0345 464 0079 or email us for an honest opinion and a quote.
Helping us quote
A few details help us give you an accurate quote. When you ask for a quote, tell us:
- Whether it’s a home or a business
- A few photos by email, if you can
- If someone has resealed it before
- The rough size of the job
Call for a quick quote, or email us if that’s easier. Tell us about the joints that need doing and we’ll talk you through the work.
Great Amwell: your questions answered
Do you cover Great Amwell for external mastic?
Yes. We work across London and the South East, and Great Amwell is part of that. Just call 0345 464 0079 or drop us an email with a few details of the job, and we will give you a clear quote.
Will you come out to Great Amwell?
Yes. Great Amwell is within the area we cover, which takes in towns, villages and rural addresses. We work across London and the South East. Just mention lanes, gates or anything else about the route when you book.
How do you reach high-level joints?
That depends on the building and the joints. We work on joints that can be reached safely. Give us some details and we will confirm the access.
Can landlords and businesses book you?
Yes, we do. Domestic, commercial and hotel work are all part of what we do.
Do the sealants smell?
Some sealants have a smell while they cure. Ventilation helps.
Should I try DIY first?
Some simple jobs can be done by a careful DIYer. Most DIY failures come from sealing over old material, wet joints or too much sealant.
Where do you work from?
We work from Crawley. We cover Great Amwell and the rest of Hertfordshire.
How long does external mastic last?
It depends on the exposure, the movement and the product. Treat it as a maintenance item and look at it yearly and renew it when it starts to fail.
Also near Great Amwell
What else we do in Great Amwell
Why it’s worth doing now in Great Amwell
Water gets in through a failed movement joint and can run behind render or cladding. Dealing with it early keeps the repair to the joint, instead of the wall and finishes around it. Around Great Amwell, older homes often have timber in their floors and frames, where water from a failed joint can cause rot if it’s left.
Instead of a standard rate, we price the job in front of us: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
Why book with us
- Tidy, careful work
- Any old sealant cut out fully, not covered over
- Domestic, commercial and hotel work
- Over 20 years’ experience
Read what affects the cost or customer reviews.
Landlords, agents and businesses in Great Amwell
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Resealing at the right time is simple maintenance that we can handle for you.
Whether it’s one flat or a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
Looking after it afterwards
No joint lasts for ever, but care makes a real difference. A few tips:
- Walk round the building once a year and look at the joints
- Keep movement joints as flexible joints, not mortar
- Show decorators and builders where the movement joints are
- Keep water from gutters off the wall
Don’t paint over the new sealant unless we’ve said the product is paintable. Many exterior sealants aren’t designed to be painted, and paint can crack as the joint moves.
Act while the splits are small. Then it’s a straightforward cut-out and reseal.
Can I do it myself?
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 does not work out, we can still put it right.
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.