Buckinghamshire · England
External Mastic in Sedrup
External mastic for Sedrup and the surrounding area: careful preparation, the right product and tidy work. Ask us for a quick quote.
- Old sealant gone brittle and cracked
- Joints pointed up with cement by mistake
- Cracked joints where brick meets render or frames
Sedrup questions
Will you come out to Sedrup?
Yes, Sedrup is covered. Our work covers London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Can you help a landlord with a rental near Aylesbury 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 send us an email with the address and what needs doing, and we’ll send you a clear quote.
Do you take out the old sealant first?
Yes, always, and completely. New silicone doesn’t stick to old silicone, so any old material comes out before anything new goes in.
Should I point up the gap in my brickwork?
No. Rigid materials can’t move with the wall. If it has already been filled, we can normally cut it out and reseal it.
Do the sealants smell?
Possibly a little. It fades as the sealant cures, and ventilation helps.
Do you hold any approvals?
Yes. We’re approved under the ARBOMaster scheme.
How long before the joint can be used?
Different products cure at different speeds, so follow the cure time we give you when we finish.
Can new sealant go over the old?
No, it will not last. It may look fine at first, but the new layer lifts away from the old one. Removing the old sealant completely is the only lasting way.
How we handle external mastic in Sedrup
Where two different materials meet, such as brick and render or blockwork and metal, they move at different rates. A flexible exterior sealant takes up that movement. If you are dealing with failed seals between different materials and panel joints letting water in, we can put it right.
Older homes in small places like Sedrup may be stone, brick or timber-framed, often with later extensions. Where one material meets another is where water generally gets in.
All our work comes with a 12-month guarantee.
- Place
- Sedrup (HP17)
- Wider area
- Buckinghamshire
- Guarantee
- One year on every job
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
How the job changes by surface
Concrete and blockwork
Concrete faces can be dusty and porous, so preparation is key. A primer goes on where the product requires one before sealing.
Joints between dissimilar materials
Brick against render, concrete against metal, stone against timber: every change of material is a joint. We seal the joint with a flexible exterior sealant.
What we do, step by step
We work through the job in order: protection first, then preparation, sealing and a tidy-up. For most jobs that takes anything from a few hours to several days, depending on the building, and the area is left clean. Somewhere as small as Sedrup, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- First we look over the joints with you, agree which to renew and talk through access.
- We cut out the failed sealant and rake out any dirt or growth.
- The joint faces are cleaned and primed where the sealant needs it.
- Backing rod goes in next, setting the depth and keeping the sealant off the back of the joint.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
Getting ready for the visit
- For indoor joints, keep the area dry beforehand if you can
- Let us know if you’ve seen damp or leaks
- Move anything stored near the joints
Get a quote
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 is easy.
Related advice
How we quote for external mastic
The quote reflects the job in front of us. We look at:
- Whether the work is at height
- How many rooms, windows or areas are involved
- The type of sealant required
- Any mould that needs treating
The cost reflects the work involved, not a rough estimate. That is why we ask a few questions first and send you a clear quote before any work starts.
Asking for a quote
Photos help, but a description is a good start. Try to tell us:
- Any access issues, like height or stairs
- What the problem is, such as mould, gaps, leaks or cracking
- The rough size of the job
- The address or postcode of the job
It all starts with a short chat. Tell us what’s wrong, where it is and how much there is, and we will talk you through what we’d do. Whenever you are ready, phone 0345 464 0079 or drop us an email.
Also near Sedrup
Also in Sedrup
Looking after it afterwards
Aftercare is simple:
- Keep water from gutters off the wall
- Never let anyone fill a movement joint with mortar
- Don’t let climbing plants root in the sealant
- Keep high-pressure jets off the joints
Have a quick look at the joints each spring. Watch for splits, edges coming away or growth in the joint.
A joint that has stopped moving pushes the movement elsewhere, usually as cracking in the brickwork or render nearby. Resealing it early helps prevent that.
Landlords, agents and businesses in Sedrup
If you manage several properties in or around Sedrup, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs, and photos by email help.
Hotels need rooms back in use, so the work can be planned room by room around your bookings where we can. We’ve worked in hotels as well as homes and businesses.
What external mastic looks like in Sedrup
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.
For site and facilities teams at buildings such as Stone Church of England Combined School, its movement joints, gutters and trims need looking after like any other building’s. In the older streets around St Mary's Church, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Sedrup is about 2 miles south-west of Aylesbury, in Buckinghamshire. Whether you’re in the middle of Sedrup or further out, external mastic is available for homes and businesses alike. Sedrup is one of 263 towns and villages in Buckinghamshire we cover for external mastic. Oxford is on our list too, around 17 miles away.
Postcode districts we cover here for external mastic: HP17. Neighbouring places we cover for external mastic include Bishopstone (1 mile south), Walton Court (1 mile east), Upton (2 miles west), Ford (2 miles south-west) and Dinton (2 miles west). Within a short drive, we also cover High Wycombe (12 miles south), Chesham (11 miles south-east), Buckingham (15 miles north-west), Amersham (13 miles south-east), Beaconsfield (15 miles south-east) and Elmhurst (3 miles north-east).
Landmarks near Sedrup
Typical jobs here are in homes near The Harrow pub, The Mandeville School and Pebble Brook School, among other places. For rail, the closest station is Aylesbury station, roughly 1.7 miles north-east. Other landmarks nearby include Dinton Castle (2.1 miles west) and Friars Square (1.8 miles north-east). Green spaces nearby include Beacon Hill and Snakemoor.
Signs you need external mastic in Sedrup
Poor preparation causes many early failures: dusty or wet faces, no primer where one was needed, or old sealant left in. The new sealant then lets go long before it should.
People normally contact us after spotting one of these:
- Weathered mastic that no longer stretches
- Cracked joints where brick meets render or frames
- Joints where the bead has come unstuck
- Movement joints with cracked, split or missing sealant
Letting a property close to Aylesbury station? Then split movement joints are easy to miss on a rental until damp shows inside.
Before booking anyone
- Whether they’re fully insured
- What guarantee comes with the work
- Is the old sealant removed completely?
- How the surfaces are prepared before sealing
Why act early in Sedrup
A low-modulus sealant is chosen because it moves without pulling hard at the edges. That matters on brick, render and concrete, which can be weaker at the face. Too stiff a sealant can pull at the edges and break them. In a small place like Sedrup, homes can be exposed to wind and rain, which finds any gap, and older walls, once damp, take a long time to dry.
Instead of a standard rate, we price the job in front of us: the amount of work, the old material and the access. You’ll know the price before we begin.
Why choose Mr Mastic in Sedrup
- Tidy, careful work
- Every job guaranteed for a year
- Sanitary silicone with an anti-fungal additive in wet areas
- Domestic, commercial and hotel work
See our cost guide and customer reviews.