External Wall Insulation in Castleknock
Upgrade your Castleknock residence to the highest thermal standard with premium Baumit external wall insulation. Our direct employed crews eliminate cold spots and protect your home with bespoke powder-coated aluminium sills from Cills.ie — with up to €8,000 in SEAI grants deducted straight from your invoice.
Castleknock External Wall Insulation & SEAI Grants
Projects typically start from €180 to €220. Isotherm deducts the SEAI grant directly from your invoice at source.
For homes subject to heavy exposure, we apply specialized silicone-based acrylic renders (such as Baumit SilikonTop) to provide exceptional rain repellency, algae protection, and vapor breathability.
For window cills where water runoff is high, we fit bespoke aluminium over-sills manufactured with a special protective powder coating from Cills.ie to guarantee 100% watertight drainage and long-term durability.
*Starting figures vary depending on project extras, architectural detailing, finish selection, silicone-based acrylic render requirements, and special powder coating for window cills. Fixed quotation provided after a free on-site survey.
Real project photos across Castleknock estates
Every home is surveyed, scaffolded, wrapped with certified Baumit graphite EPS, and completed with custom aluminium window sills by our own direct crews.
Georgian Village Estate, Castleknock, Dublin 15
1980s 5-Bed Detached Residence
System: Baumit ProSystem 140mm Graphite EPS (λ 0.031)
Finish: Baumit NanoporTop Self-Cleaning Silicone Render (Chalk White 0019)
Sill Detail: Bespoke powder-coated aluminium sills by Cills.ie in RAL 7016 Anthracite Grey
BER Upgrade: E2 (370 kWh/m²/yr) → A3 (72 kWh/m²/yr with Solar PV)
Solid masonry exterior envelope fully sealed. Custom architectural sills fitted across 16 window openings; cold spots eliminated in all north-facing bedrooms.
Laurel Lodge Estate, Castleknock, Dublin 15
1970s 4-Bed Semi-Detached House
System: Baumit ProSystem 120mm Graphite EPS
Finish: Baumit SilikonTop 1.5mm Silicone Render (Pebble Grey 0876)
Sill Detail: Aluminium sills with welded end caps fabricated by Cills.ie
BER Upgrade: D2 (295 kWh/m²/yr) → B1 (84 kWh/m²/yr)
Solid concrete blockwork and uninsulated gable wall wrapped. Gas meter and ESB supply brackets unclipped and remounted on certified standoff brackets.
Carpenterstown Park Estate, Castleknock, Dublin 15
1990s 3-Bed Semi-Detached Home
System: Baumit OpenSystem Breathable Composite Wrap
Finish: Baumit SilikonTop 1.5mm Texture (Oatmeal Cream 0244)
Sill Detail: Powder-coated aluminium sills by Cills.ie in RAL 9016 White
BER Upgrade: D1 (250 kWh/m²/yr) → B1 (80 kWh/m²/yr)
Thermal bridging at front bay window and concrete floor perimeter eliminated. Homeowner reported an immediate 42% drop in winter heating runtime.
External wall insulation questions in Castleknock
How much does external wall insulation cost in Castleknock in 2026?+
A job typically starts from €180 to €220. Final figures depend on extras, architectural details, and chosen finishes — such as whether silicone-based acrylic render is required for enhanced weather resistance, and whether window cills subject to high water runoff require special powder coating. As an SEAI Registered Contractor (#10423), Isotherm deducts your SEAI grant (up to €8,000 for detached, €6,000 for semi-detached/end-terrace, €3,500 for mid-terrace, and €3,000 for apartments) directly from your invoice at source.
Do I need planning permission for external insulation in Castleknock?+
For standard residential estates across Castleknock (including Laurel Lodge, Carpenterstown, Riverwood, and Diswellstown), external wall insulation falls under Exempted Development under Section 4(1)(h) of the Planning and Development Act 2000. If your home is a designated Protected Structure or in an Architectural Conservation Area in historic Castleknock Village, consultation with Fingal County Council is required. We evaluate planning and boundary clearances during your on-site survey.
Why is Baumit silicone render recommended for Castleknock properties?+
Castleknock features leafy, mature residential estates with large gardens and mature tree canopies. Standard renders can collect dirt and foster green algae. We install NSAI-certified Baumit systems finished with Baumit SilikonTop or NanoporTop self-cleaning silicone renders that actively resist organic dirt and wash clean with rainfall, keeping your facade spotless without repainting.
How fast can Isotherm crews reach Castleknock from your depot?+
Our operations base and fabrication workshop are located at Unit 20, Westlink Industrial Estate, Kylemore Road, Inchicore, Dublin 10, D10 TD35. Our direct crews travel via the Chapelizod bypass or M50/N3 to arrive in Castleknock within 12 to 18 minutes, ensuring daily on-site project management and consistent quality control.
How are window sills detailed during a Castleknock house wrap?+
Adding 100mm to 150mm of external insulation requires extended, precision-engineered sills. We install bespoke powder-coated aluminium window sills fabricated by our sister workshop Cills.ie in our Inchicore depot, featuring welded watertight end caps and thermal break insulation to prevent water ingress and thermal bridging.
Can I qualify for the SEAI grant if my Castleknock home was built in the 1990s or 2000s?+
Yes. Any home built and occupied on or before 31 December 2010 qualifies for the SEAI Better Energy Homes grant. Furthermore, under the 2026 SEAI second wall measure rules, homes that previously received a cavity bead injection grant can now claim the full €6,000 to €8,000 external wall insulation grant.
Book your Castleknock Baumit house wrap survey
Our own direct installation crews survey, wrap, and render homes across Castleknock. Guaranteed fixed-price quotes with SEAI grants up to €8,000 deducted directly from your invoice.
