How We’re Insulating Our 7-Storey Solid Concrete Tower Home | Expert Insight, by Our Tower Home on YouTube. 20 min 37 s.
- Video length
- 20 min 37 s
- Time to do it
- 2 to 3 days per room
- Difficulty
- Takes practice
- Steps
- 9
What you need
Steps
Find the cold spots before you buy anything. A hygrothermal check such as WUFI shows where moisture will collect inside the wall and how thick the insulation needs to be.
Deal with ground moisture first. Clean the below-ground concrete and apply a deep-penetrating tanking slurry such as Watstop to hold rising damp back.
On floors, lay a lightweight insulating screed such as Diasen Thermostep so the floor surface stays well above the dew point.
Fix lathing to ceilings and wall junctions, then plaster over it to break the thermal bridges at floor and ceiling bands.
Apply a breathable cork and lime insulating plaster in two coats, building up the thickness the wall needs. It lets vapour through while blocking draughts.
On curves and bay windows, keep the plaster thickness even and use a curved float so no thin, cold patches are left.
Box in concrete downstand beams with high-capillarity calcium silicate boards. Tape the joints and skim over them.
Fit high-density thermal break boards under window sub-frames and at the roof junction to cut cold bridging.
Let the plaster dry slowly, then ventilate bedrooms daily and keep the room warm so the window glass stays above the dew point.
Tips and common mistakes
Avoid non-breathable foam boards on solid concrete. They trap moisture and push condensation deeper into the wall.
Condensation on bedroom windows is often a ventilation and heating problem first, so fix airflow before spending on insulation.
Dry washing outside and run an extractor fan in the bathroom and kitchen to keep indoor humidity down.
Cork and lime plasters are A1 fire rated, which makes them a safer choice than plastic foams on escape routes.
Questions
Why do my bedroom windows get wet every morning?
Warm, moist air from breathing and drying laundry hits the cold glass and condenses. Better ventilation and warmer surfaces fix it.
Will breathable insulation stop condensation on the windows?
It warms the wall surfaces and cuts cold bridging, but the glass stays cold. You still need to ventilate and keep humidity low.
Can I just glue foam board to the inside of a solid concrete wall?
Not safely. Foam traps moisture in the concrete, which can cause damp and mould. Use a breathable, capillary-active system instead.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
