How to Install ISO-THERM Internal Wall Insulation (Video Guide)

Waterproofing How-To Guides › Specialist Insulation › ISO-THERM

Watch the full step-by-step demo above. Watch on YouTube
ISO-THERM Installation: Step-by-Step Guide

Wykamol ISO-THERM is an internal insulation and condensation control board designed to raise wall surface temperature, helping to reduce condensation and mould regrowth on cold walls and corners.

Important: ISO-THERM helps with condensation and cold surfaces. If you have an active leak, water ingress or rising damp, fix the cause first before insulating.
Practical steps FAQ included Condensation control tips
In this guide:
  • Wall assessment & prep
  • Board fitting overview
  • Aftercare & condensation reduction

Tip: best results come from insulation + steady ventilation and humidity control.


Overview

Condensation forms when warm, moist air hits a cold wall surface. ISO-THERM helps by improving surface temperature, reducing the likelihood of moisture forming — which supports long-term mould reduction when used correctly.

Use the steps below as a quick checklist while watching the video above.

What you’ll need

  • ISO-THERM boards
  • Recommended adhesive (per manufacturer guidance)
  • Measuring tape, straight edge, knife/saw
  • Level & pencil for setting out
  • Finishing materials suitable for the room

Where this works best

  • Cold external walls & corners
  • Bedrooms with morning condensation
  • Basements (with ventilation)
  • Solid wall properties with cold spots

Step-by-step: ISO-THERM installation overview

Step 1: Check and prepare the surface

Ensure the wall is clean, dry and sound. Remove loose paint or flaky material. If you suspect active ingress or leaks, resolve those first before installing insulation.

Step 2: Measure, cut and set out boards

Measure the area, mark cut lines and plan joints neatly. Reducing gaps helps minimise thermal bridging at corners and edges.

Step 3: Fix boards using the specified method

Apply adhesive as recommended for your substrate, press boards firmly into place and keep them level. Follow curing times before finishing.

Step 4: Finish & reduce humidity

Complete the finishing layer as specified, then reduce humidity with ventilation (extractors, trickle vents, regular airing) to keep condensation low long-term.

FAQs

Is ISO-THERM for condensation or damp?

ISO-THERM primarily targets condensation by warming cold wall surfaces. If you have rising damp or active ingress, the cause must be addressed first.

Will it help with mould?

It helps reduce the conditions mould thrives in by lowering condensation risk. For best results, improve ventilation and keep indoor humidity under control.

Do I still need ventilation?

Yes — insulation helps, but consistent ventilation (especially in bedrooms and basements) is key for long-term condensation control.

Need technical advice? Call our team on 01268 472358 and we’ll help you choose the right solution.

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