Oxfordshire · England
St Clement's External Mastic
We cover St Clement's for sealing brickwork movement joints, render, cladding and façade joints. Old sealant removed completely, joints prepared properly.
- Moss and dirt in joints with no sealant left
- Hard, crazed mastic that has stopped moving
- Brick movement joints where the sealant has split
How the job changes by surface
Joints between dissimilar materials
Different materials may need different primers. Both surfaces are cleaned and primed as the product requires.
Concrete and blockwork
Concrete faces can be dusty and porous, so preparation is key. We prime where the sealant needs it.
External mastic for homes and businesses in St Clement's
Short cuts in external joints show up within a season or two. New sealant over old, joints packed with mortar and beads with no backing rarely last long. We strip the joint back and start again. We work on joints between brick and frames, copings & trims and concrete & block, and people most often call us about weathered mastic that no longer stretches and joints pointed up with cement by mistake.
In a smaller place like St Clement's, some homes face open ground, and walls and rooflines facing the weather take the worst of it. Joints on those sides are normally the first to go.
Big or small, it’s backed by our 12-month guarantee in St Clement's and across Oxfordshire.
- Where
- St Clement's (OX4, OX1, OX3)
- Wider area
- Oxfordshire
- Guarantee
- A year, on every job
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Looking after it afterwards
A little care helps the new joints last. Our advice:
- Avoid pressure-washing directly into sealant joints
- Never let anyone fill a movement joint with mortar
- Keep water from gutters off the wall
- Leave the joints unpainted unless we have said otherwise
Have a quick look at the joints each spring. Watch for splits, edges coming away or growth in the joint.
Water getting behind cladding or render can go unnoticed for a long time. When it finally shows inside, the joint may have been open for years so early resealing is worth it.
Honest limits
We won’t take on work that will not last, so here’s what sealant can’t put right:
- Cracking across the wall rather than at a joint
- Walls that need new movement joints cut into them
- Failed render or damaged cladding panels
Not sure which it is? You can phone 0345 464 0079 or send us an email and we will tell you honestly.
Surfaces we seal
- Façade panels
- Brickwork movement joints
- Copings & trims
- Render & cladding joints
- Concrete & block
- Joints between brick and frames
When to call us in St Clement's
Poor preparation causes many early failures: joint faces that were dusty or damp, unprimed where they needed it, or still carrying old sealant. The new sealant then lets go long before it should.
The problems people usually mention when they call include:
- Cracked joints where brick meets render or frames
- Weeds or debris growing in open joints
- Hard, crazed mastic that has stopped moving
- Leaking joints around cladding and façade panels
For site and facilities teams at buildings such as East Oxford Primary School, larger buildings have long runs of movement joint that eventually need resealing.
What to look for in a quote
- Who does the work, and how experienced they are
- Whether all the old sealant comes out first
- Is VAT in the price?
- Which sealant they’ll use, and why
What external mastic looks like in St Clement's
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. With historic houses such as Holywell Manor (about 0.5 miles north-west) nearby, there’s older building stock in the area around St Clement's as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
If you live in an older home near St Clement's Church, an extension built onto an older house moves differently, and the joint between them takes the strain. If you let a flat or house near Oxford station, split movement joints are easy to miss on a rental until damp shows inside.
St Clement's is about 1 mile west of Oxford, in Oxfordshire. We provide external mastic to homes and businesses in St Clement's and the surrounding area. St Clement's is one of 443 places in Oxfordshire where we work for external mastic.
We work across OX4, OX1 and OX3 for external mastic. Whether your property is on Rose Lane, Alma Lane and Avenue Lane or a nearby road, we can help. If you are just outside St Clement's, we cover Oxford (1 mile east), Headington Hill (1 mile north-east), St. Ebbes (1 mile west), New Marston (1 mile north) and Donnington (1 mile south). We also work in nearby towns such as Didcot (10 miles south), Bicester (11 miles north), Abingdon-on-Thames (5 miles south), Witney (11 miles west), Carterton (15 miles west) and Thame (12 miles east).
Near you in St Clement's
Typical jobs here are in homes near Cheney School, Alexander Library of Ornithology and Oxford Media & Business School, among other places. Other local landmarks include Headington Hill Park (under half a mile north-east) and Oxford Coach & Horses pub (under half a mile east). St Clement's’s nearest station is Oxford station, about 1.3 miles west of the centre. Other landmarks nearby include Oxford Castle (0.9 miles west) and Frank Cooper Marmalade Museum (under half a mile west). Not far away are CS Lewis Nature Reserve and Headington Hill.
DIY sealant or a professional job?
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and the joint depth matters as much as the finish.
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
Places near St Clement's
Other services in St Clement's
Common questions in St Clement's
I let a flat near Oxford station. Can you help?
Yes, we work for landlords and letting agents. Just call 0345 464 0079 or send us an email and tell us about the property, and we’ll send you a clear quote.
Is St Clement's within the area you cover?
Yes, we do. Our work covers London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Is the work guaranteed?
Yes, always. Each job is guaranteed for twelve months.
How long should I leave it?
That depends on the sealant used, so follow the cure time we give you.
Do you take out the old sealant first?
Yes, always, and completely. New sealant won’t bond properly to old, so the joint is cleaned back first.
Do you hold any approvals?
Yes. We hold ARBOMaster approved applicator status, and we’re fully insured.
How do I get a quote for external mastic in St Clement's?
The cost depends on the size of the job, access and how much old sealant has to come out. Ask us for a quote and we’ll talk you through it.
Can you quote for more than one area?
Yes. Several rooms, windows or areas can go on one quote.
Landlords, agents and businesses in St Clement's
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance.
Hotels need rooms back in use, so we plan the work room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
How the visit works
You do not need to clear the whole room or building, only the area right around the joints. Everything nearby is protected, and the work takes anything from a few hours to several days, depending on the building in most cases. In a smaller place like St Clement's, parking is seldom the issue; lanes, gates and long drives are worth mentioning. If the job is outside, tell us about side access and how high the joints are.
- We start by checking each joint, agreeing the ones to redo and how we will reach them.
- Old sealant and any debris are cut and raked out.
- 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.
- The new sealant, chosen to suit the brick or render, is applied and tooled to a neat finish.
Getting ready for the visit
- Tell us about any previous sealing or DIY attempts
- Let us know if you’ve seen damp or leaks
- Keep children and pets away from the work area
Ask for a quote
For a quick quote, get us on the phone, or send an email if you’d rather. Tell us about the joints that need doing and we’ll explain what’s involved and send you a clear quote.