Insulation Above And Between The Rafters – Sitework

Insulating above and between the rafters

When working at a height ensure risk assessments have been carried out and that all necessary protective measures are in place.

Do not walk on Ballytherm boards nor use them as a working platform.

Installation sequence (working from the outside)

  1. Fit battens to the sides of the rafters 
to support the between rafter insulation.
  2. Cut Ballytherm insulation to fit tightly between the rafters. Set insulation on the battens.
  3. Fix a stop batten across the ends of the rafters.
  4. Lay the first row of Ballytherm insulation boards across the rafters, resting firmly against the stop batten. Tack in place with clout nails.
  5. Lay the next rows of Ballytherm insulation boards. Stagger board junctions between rows.
  6. Fix counterbattens to the rafters.*
  7. Lay the underlay, following manufacturer’s instructions.
  8. Install the roof covering
* where the underlay is installed under the counter-battens reverse the order of points 6 and 7.

Points to watch

  • Cut boards to fit neatly around penetrations such as SVPs.
  • Seal gaps and junctions with expanding foam.


Further Advice & Information

For more information about Ballytherm products, technical advice, or guidance on the suitability of our products for your project, contact us at + 353 (0)49 95 27000,, email us at or use our contact form.

Floor Insulation


Design Guidance