A Modern, Breathable & Ultra-Thin Alternative to Traditional IWI
Our high-performance Corksol Internal Wall Insulation coatings are an eco-friendly, ultra-thin internal wall insulation system that delivers outstanding thermal performance without the disruption, bulk, or moisture issues associated with traditional methods.
Whether you’re improving the efficiency of a solid-wall home, renovating a period property, or seeking an alternative to insulated plasterboard, Corksol offers exceptional versatility and long-term benefits.
“ProGuard Exteriors is an excellent company to deal with and we cannot recommend them highly enough. Their teams are reliable, efficient, effective and a pleasure to deal with. The end results they have produced on our exterior walls are superb. Thank you very much from David and Barbara.”
15 Years of Interior Wall Expertise
Tailored, breathable solutions engineered for lasting comfort
Fully Accredited & Certified
TrustMark‑registered, PAS 2035‑certified installers
Quality You Can Count On
We only use premium materials, never compromise on workmanship
Homes across the UK are losing up to 35% of their heat through uninsulated walls.
Corksol is a spray-applied natural cork coating that provides thermal insulation, acoustic comfort, condensation control, and breathability in a thin, seamless layer.
Corksol is the ideal choice when…
You want insulation that does not reduce room size
Your walls must stay breathable
You own a solid-wall or heritage property
You want a fast, clean installation
Moisture management is a priority
Traditional IWI is more suitable when maximum U-value reduction is required and space is not an issue. However, for most homeowners balancing aesthetics, comfort, space, and moisture control—Corksol is the superior modern solution.
Now applying Corksol for exceptional durability and performance.
Ultra-Thin Thermal Performance Corksol can improve wall U-values and internal warmth with a build-up as thin as 8–12mm, helping preserve room sizes—ideal for small bedrooms, hallways, or tight spaces.
Reduces Heat Loss & Lowers Energy Bills The natural thermal resistance of cork significantly reduces heat transfer through external walls, improving comfort and energy efficiency.
Breathable & Moisture-Regulating Corksol allows walls to breathe naturally, preventing trapped moisture and reducing the risk of condensation and mould. Perfect for older or solid-wall buildings where vapour barriers can cause problems.
Seamless and Flexible Application Sprayed directly onto existing plaster or masonry, creating a continuous coating with no cold-bridging risks and minimal disruption to the household.
Eco-Friendly & Sustainable Made from 100% natural cork, harvested without cutting down trees. Cork regenerates every nine years—making Corksol one of the most sustainable insulation materials available.
Improves Acoustic Comfort Cork’s natural sound-dampening qualities help reduce airborne noise from outside or neighbouring rooms.
Fire-Resistant, Hypoallergenic & Non-Toxic A safe and healthy choice for homes, schools, and commercial interiors.
Compatible with Multiple Finishes Can be left as a decorative finish or skimmed/plastered over for a traditional look.
Solid Wall Homes (Pre-1930 Properties) Improves thermal performance without altering external appearances or adding thick layers inside.
Heritage & Listed Buildings Perfect for areas where traditional insulation cannot be installed due to restrictions or structural sensitivity.
Small Rooms or Narrow Spaces Achieve insulation without losing valuable interior space.
Rooms Prone to Condensation Provides natural moisture regulation—ideal for…
Bedrooms Living rooms Home offices Cold corners and bridging points
Hard-to-Insulate Areas Curved walls, awkward shapes, chimney breasts, and irregular surfaces where rigid boards are difficult to install.
1. Decorative Corksol Finish (Spray Granule) Textured, natural appearance Breathable and durable Available in a wide range of colours
2. Smooth Plaster Finish Corksol base layer for insulation Finished with a traditional skim coat Perfect for homeowners wanting a seamless, painted wall
3. Painted Finish Any standard emulsion can be applied Maintains breathability when paired with vapour-open paints
4. Hybrid Systems Corksol insulation base + specialist breathable finishing plasters for enhanced thermal and aesthetic performance
1. Consultation & Survey We assess wall conditions, moisture levels, and insulation requirements.
2. Surface Preparation Cleaning, repairs, bonding coats where necessary
3. Corksol Spray Application Applied in multiple thin, controlled layers for optimal performance
4. Finishing Layer Choose from decorative finishes, plaster skim, or paint-ready surface
5. Quality Checks & Aftercare We ensure your insulated walls perform as expected—now and long into the future
Excellent company to deal with
“ProGuard Exteriors is an excellent company to deal with and we cannot recommend them highly enough. Their teams are reliable, efficient, effective and a pleasure to deal with. The end results they have produced on our exterior walls are superb. Thank you very much from David and Barbara.”
Excellent job on a difficult house
“ProGuard have done an excellent job on a difficult house requiring a number of different treatments. Thanks especially to Dave who coordinated much of the work, and his colleagues who worked extremely hard to finish it.”
High-quality work and great communication
“Throughout the time of this CorkSol project we found the team very easy to work with. They communicated clearly, responded quickly to our requests and were polite and helpful. The quality of the workmanship was high and the finished treatment met our expectations completely. The site was left completely clean and clear of debris. Asen and his team and David worked hard to give us complete satisfaction. We highly recommend ProGuard as an applicator of CorkSol.”
Certified Corksol Approved Installers delivering trusted insulation
Experienced in both modern and heritage properties
Professional guidance on moisture, insulation, and internal finishes
High-quality workmanship with full system warranties
Clean, efficient and minimally disruptive installations
Whole-property approach supporting long-term performance
What services do you offer?
ProGuard Exteriors are trusted experts in exterior wall coatings, internal wall insulation, rendering, spray cork coatings, and external facade refurbishment. Our full suite of wall coating and rendering services include…
CorkSol SprayCork Coatings
CorkSol Internal Wall Insulation
Exterior Wall Coatings
External Wall Rendering
Where do you operate?
ProGuard Exteriors are based in Aylesbury and proudly serve homeowners and businesses across Oxfordshire, Buckinghamshire, Hertfordshire, Berkshire, Surrey, and London — and throughout the wider South East.
What is CorkSol SprayCork?
CorkSol SprayCork is a sustainable, spray-applied cork render that provides exceptional thermal insulation, weather protection, and breathability. It’s an eco-friendly alternative to traditional wall coatings and renders, offering a smooth, durable, and stylish finish.
How long do your coatings and renders last?
Our wall coatings and renders are designed for long-term protection, with lifespans of up to 25 years depending on the finish and maintenance.
Are your products and services guaranteed?
Yes — all our installations are fully guaranteed, with product warranties of up to 25 years. We’re also TrustMark and QualityMark endorsed, PAS-accredited, and CorkSol-approved applicators for your peace of mind.
Do you offer free quotes or surveys?
Absolutely! We provide free, no-obligation quotes and surveys to assess your property’s needs and recommend the best solution for your home.
Is SprayCork suitable for all property types?
Yes — SprayCork can be applied to most surfaces, including brick, render, stone, and existing coatings. It’s ideal for both modern homes and older properties in need of breathable, long-lasting protection.
How long does installation take?
Project times vary based on property size and finish type, but most exterior wall coating or rendering jobs are completed within a few days by our experienced installers.
Book your free, no-obligation survey today. Our experts will assess your property and recommend the perfect wall coating or render to enhance it’s appearance and protection. You’ll also receive a clear, fast quote with no obligation.
03316 300 082
enquiries@proguardexteriors.co.uk
4 Cromwell Court, New Street, Aylesbury, Buckinghamshire HP20 2PB
Monday to Friday 8:00am - 6:00pm / Weekends - Closed
What service are you interested in?