Oxfordshire · England
External & façade joints in Sydenham, Oxfordshire
Problem with your movement joints in Sydenham? We remove the old material, prepare the joints and seal them properly, with a 12-month guarantee.
- Failed sealant between panels on a façade
- Sealant that has lost its bond to the brick or render
- Rain getting behind render or cladding at a joint
External mastic in Sydenham, done properly
Joints between dissimilar materials, like brick against render or concrete against a steel frame, see movement from both sides. A flexible exterior sealant takes up that movement where mortar or filler would crack. If you’re dealing with joints with sealant missing in places and failed sealant between panels on a façade, we can put it right.
External sealant needs dry, clean surfaces, so work around Sydenham is planned for dry weather. Tell us about access to all sides of the building, including outbuildings and garages.
Big or small, you get the same one-year guarantee.
- Where
- Sydenham (OX39)
- Wider area
- Oxfordshire
- Guarantee
- One year on every job
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
What we can’t put right
We will always be straight with you, so here’s what sealant can’t fix:
- Cracking across the wall rather than at a joint
- Render that’s blown, hollow or coming away
- Movement that is more than a sealant joint can take
If you’re not sure, just ring 0345 464 0079 or email us and we will give you a straight answer.
Joints and surfaces we work on
- Render & cladding joints
- Brickwork movement joints
- Concrete & block
- Copings & trims
- Façade panels
- Joints between brick and frames
Keeping the joints in good condition
So the new joints stay in good condition:
- Never let anyone fill a movement joint with mortar
- Avoid pressure-washing directly into sealant joints
- Tell anyone working on the walls about the movement joints
- Deal with leaking gutters that soak the joints below
Only paint over the joint if we’ve confirmed the sealant can take paint. Many exterior sealants are not designed to be painted.
Small splits are the time to act. At that stage it’s a simple cut out and reseal before water has had years to get in.
External mastic in Sydenham: local notes
With historic houses such as Adwell House (about 2.4 miles south-west) nearby, there’s older building stock in the area around Sydenham as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Homes close to Church of St Mary include some older properties, and old and new materials meet at the roofline and walls, which is where sealant earns its keep. For landlords with property near Haddenham & Thame Parkway station, outside joints that have cracked can let damp into a rental, so check them between lets.
Sydenham is about 3 miles south-east of Thame, in Oxfordshire. Across the OX39 area, our applicators can take on external mastic. 443 places in Oxfordshire are on our list. There’s also a page for Oxford, about 13 miles away.
Jobs for external mastic in OX39 works the same way as everywhere else we cover. Other places close to Sydenham include Kingston Stert (1 mile south-west), Emmington (1 mile north-east), Chinnor (2 miles east), Towersey (2 miles north) and Thame (3 miles north-west). We also work in nearby towns such as Oxford (13 miles west), Didcot (15 miles south-west), Abingdon-on-Thames (15 miles west), Henley-on-Thames (12 miles south), Benson (9 miles south-west) and Headington Quarry (11 miles west).
Local landmarks in Sydenham
Typical jobs here are in homes near The Crown Inn and the streets around them. The nearest railway station is Haddenham & Thame Parkway station, about 4.3 miles north. Other landmarks nearby include Thame Museum (3.2 miles north-west) and Thame Community Hospital (2.7 miles north-west). Not far away are Bald Hill and Oakley Hill nature reserve.
What happens on the day
Before we leave, we go over the finished joints with you and tell you how long to leave it. The visit itself usually takes anything from a few hours to several days, depending on the building, depending on the amount of work. For a village or hamlet like Sydenham, the journey is planned in advance: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- Each joint is checked and the colour of the new sealant agreed.
- Failed sealant is removed back to clean, sound faces.
- Backing rod goes in so the sealant can stretch between the two faces.
- Primer is applied wherever the sealant needs it.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Before we arrive
- Let us know about earlier repairs to the joints
- Where the joints are inside, avoid wetting them before we arrive
- Keep pets and children clear of the area while we work
Ask for a quote
Asking for a quote is easy: let us know what needs doing and where. A few pictures by email make the job easier to understand.
Advice
Surface by surface
Brickwork movement joints
Brick walls have vertical movement joints to absorb expansion. We reseal them with a low-modulus sealant over backing rod in a colour to suit the brick.
Render joints
Rendered walls have joints at beads, openings and changes of material. We reseal them with a flexible exterior sealant that suits the render colour.
Should I try it myself first?
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 fails, we can still redo it.
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and doesn’t move well, and getting the depth right matters as much as the look.
What affects the cost of external mastic
You’ll get a clear quote before work begins. It takes into account:
- Any mould that needs treating
- Which sealant suits the joint
- The amount of work
- How easy the joints are to reach
No two jobs are quite the same, so we quote each one individually. Size, access and the product the joint needs all make a difference.
Asking for a quote
Photos help, but a description is a good start. Try to tell us:
- The address or postcode of the job
- 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 send an email if you’d rather. Tell us about the joints that need doing and we’ll explain what’s involved.
FAQs for Sydenham
Do you cover smaller places like Sydenham?
Yes, Sydenham is covered. Our work covers London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Is Sydenham in your area for external mastic?
Yes, Sydenham is within the area we cover. Our work covers London and the South East. You can call 0345 464 0079 or drop us an email and tell us what needs doing.
Do you do commercial work?
Yes. We work in offices, washrooms, hotels and other commercial premises, as well as homes. Working times can be discussed when we quote.
Do you hold any approvals?
Yes. We’re approved under the ARBOMaster scheme, which is run for the Arbo sealant brand.
Do I have to be there?
It depends on the job. For work indoors, someone needs to let us in, while outside work can sometimes be arranged differently.
Do you take out the old sealant first?
Yes, every time. New sealant will not bond properly to old, so the joint is cleaned back first.
Can you quote for more than one area?
Yes, we can. Several rooms, windows or areas can go on one quote.
Will it make a mess?
We keep the work tidy. We protect what’s around the joints, and we clear up when we’re done.
Also in Sydenham
Landlords, agents and businesses in Sydenham
Businesses can book us for washrooms, kitchens, offices and more. For commercial premises, we can talk through working times when we quote.
We regularly work with letting and managing agents. Tell us the address, the job and how access works.