Oxfordshire · England
New Build Mastic in Cumnor
New build mastic for Cumnor, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- New-build shower sealant that has already split
- Frame joints opening as the plaster dries
- Sealant work across a run of new homes
About our new build mastic in Cumnor
Across Cumnor, we work for both new-home owners and the builders handing those homes over. One shower or a whole phase of plots, the method does not change: cut out, clean, prime where needed and reseal neatly. If you are dealing with beads laid onto grit and dust from the build and cracked sealant around new window and door frames, we can put it right, whatever the surface.
Work in a small place like Cumnor just needs the journey and access planning, and once on site, the job is the same as anywhere.
All of our work is guaranteed for twelve months, and the guarantee is the same wherever you are.
- Place
- Cumnor (OX2)
- Region
- Oxfordshire
- Cover
- A year, on every job
- Price
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
How we quote for new build mastic
Your quote is based on your job. We take into account:
- Whether old sealant or filler has to be cut out
- Whether there’s mould to deal with
- Whether the work is at height
- The number and length of the joints
Instead of a standard rate, we look at what your job involves: the amount of work, the old material and the access. The price is agreed before we begin.
Helping us quote
The more you tell us, the more accurate the quote. When you get in contact, it helps to mention:
- A few pictures by email, if you can
- Any previous sealing or DIY work
- Where the property is
- The problem you’ve noticed
We quote each job on its own. Just phone 0345 464 0079 or drop us an email with the details and send pictures if you have them.
Places near Cumnor
More services for Cumnor
Why deal with it now?
A tube of sealant from the DIY shop will not fix the cause: dust, no primer and old sealant left in the joint. Cutting out, cleaning and priming are what make the difference. In a small place like Cumnor, homes can be exposed to wind and rain, which finds any gap, and damp in older walls is slow to dry out.
We do not show prices on the website, because the cost depends so much on the job itself. For a quick quote, please call 0345 464 0079 or send us an email and we will talk you through it.
Why choose Mr Mastic in Cumnor
- Old sealant always removed completely
- Sanitary silicone with an anti-fungal additive in wet areas
- Tidy, careful work
- We agree the colour with you first
What we do, step by step
We work through the job in order: protection first, then preparation, sealing and a tidy-up. Typically it takes a few hours in a single home. Somewhere as small as Cumnor, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- We look at why each joint failed, including any movement.
- Old sealant is cut out and the joints cleaned.
- We make sure the joints are dry and prime them if needed.
- New sealant goes in, with baths filled first so they’re at their heaviest.
- We check every joint and leave you with the cure times.
Before we arrive
- Let us know about earlier repairs to the joints
- Clear the area around the work
- Mention any parking rules near the property
Get a quote
For a quote, ring 0345 464 0079 or send us an email and tell us where the job is and what the problem looks like. We will send you a clear quote before any work starts.
Related advice
Landlord and commercial work in Cumnor
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements.
If you manage several properties in or around Cumnor, several properties can go on one quote. Just tell us the addresses and what each one needs.
Keeping the joints in good condition
To keep the joints looking good and working properly:
- Clean sealant with mild detergent, not abrasives
- Keep pictures and emails about snagging items
- Avoid running a DIY bead over the old one
- Look at the sealant regularly in the first couple of years
Keep pictures of the joints and any snagging correspondence with your builder. It’s useful if you need to raise other issues later.
The sooner you deal with untidy or cracking sealant, the less there is to put right. Left alone, a small crack can become a leak over time.
Questions from Cumnor
Is Cumnor in your area for new build mastic?
Yes, Cumnor is within the area we cover. We work across London and the South East. Just ring 0345 464 0079 or drop us an email with a few details of the job, and we’ll give you a clear quote.
Do you work for landlords with property near Oxford station?
Yes, rental work is part of what we do. Just phone 0345 464 0079 or send us an email and tell us about the property, and we will give you a clear quote.
Do you take on second-fix sealing for builders?
Yes. We seal plots to the developer’s programme, room by room. Tell us the plots and the joints involved for a clear quote.
Will you leave a mess?
Very little: the area around the joints is protected first, and we clear up the old sealant and our materials before we leave.
When is the sealant fully cured?
It depends on the product and the temperature. Before we leave, we will tell you the cure time.
What information do you need?
Where the job is, what the problem is and roughly how big it is. Photos by email help too.
Can you quote for more than one area?
Yes, and it often makes sense. Combining jobs makes good use of the visit, so mention them when you ask for a quote.
Can you reseal over the builder’s sealant?
No. We always remove the existing bead, the joint cleaned and primed where needed, before resealing.
Should I try it myself first?
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
If you’ve already had a go yourself, that is fine. We cut it out and start again, so just mention it when you contact us.
Different surfaces, different methods
Kitchens
Worktops in new homes can move slightly as the house dries, which opens gaps along the back. A fresh flexible bead closes them.
Plot handovers
Plot mastic is carried out to the developer’s schedule. Each joint is cleaned and primed where needed so the sealant lasts.
Joints and finishes in Cumnor homes
London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
In and around Cumnor, as anywhere, good new build mastic starts with a clean, dry, properly prepared joint. For new homes near Oxford station, it’s worth checking the sealant early, while snags are still fresh.
Cumnor is about 4 miles north-west of Abingdon-on-Thames, in Oxfordshire. Homes, rented property, offices and hotels in Cumnor can book us for new build mastic. The work is guaranteed for a year. 443 places in Oxfordshire are on our list.
Jobs for new build mastic in OX2 works the same way as everywhere else we cover. Streets in the area include High Street, The Park and The Winnyards, all of which we cover. Neighbouring places we cover for new build mastic include Chawley (1 mile north-east), Filchampstead (1 mile north-west), Henwood (1 mile south-east), Dean Court (2 miles north-east) and Botley (2 miles north-east). Further out, we also cover Oxford (5 miles east), Didcot (9 miles south-east), Bicester (14 miles north-east), Abingdon-on-Thames (4 miles south-east), Witney (8 miles north-west) and Carterton (11 miles west).
What’s near Cumnor
Typical jobs here are in homes near The Vine Inn and Matthew Arnold School. The closest station to Cumnor is Oxford station, roughly 3.1 miles north-east of the centre. A little further out are Westgate Shopping Centre (3.3 miles north-east) and Radcliffe Infirmary (3.6 miles north-east). Not far away are Lashford Lane Fen and Cumnor Hill.