Fibreglass roof to Kitchen Extension in Twickenham

  • Location: Twickenham TW2
  • Project type: New Fibreglass Roof and Velux Windows Installation
  • Project Duration: 5 weeks

TipTop Builders have been asked to completely redo the outdated kitchen extension roof in Twickenham TW2. The idea was to bring more natural lighting into the kitchen and dining room and to install a roof that will last for ages. The scope of the completed jobs is:

  1. Installation of GRP Fibreglass Roof
  2. Two large Velux windows installation
  3. One sun tunnel installation
  4. New roof insulation.
  5. New ceiling and spotlights to the kitchen and dining room
  6. Decoration works on the whole ground floor. 

Check out photos of BEFORE – IN PROGRESS – COMPLETION to get an idea of the number of required works


Leaky old Flat Roof


outdated flat roof TW2


outdated flat roof Twickenham

1. Old Felt Roof

There are 2 layers of felt and some joists are rotten due to a leak. We will remove everything up to the joists and start fresh.


flat roof double joists


flat roof framework


flat roof firrings

2. Flat Roof Construction

We install double joists for all Velux windows and sun tunnel, reinforce existing joists with noggins and joists hangers. To achieve the required slope of 1cm for every 60cm builders nail firrings on all roof joists.


flat roof insulation


window upstand installation


roof insulation


roof boards OSB

3. Insulation and OSB boards

It is time for Earthwool 200mm insulation to go between joists. Then we use 18mm T&G OSB boards to deck the roof. It makes sense to apply pipe insulation on pipework to eliminate a chance of heat loss and condensation. Once it is done TipTop Builders fit Velux windows upstand with carbon steel self-drilling screws. 


apply fibreglass mat Twickenham


apply GRP mat Twickenham


rooting resin base coat Twickenham

4. Fibreglass Mat and Base Coat

Make sure OSB boards are dry and clean. Builders cut and nail raised edge and facia GRP trims, external and internal corners. Then we mix the base coat with hardener (taking into account surface temperature and required amount), cut and fit reinforced fibreglass mat with GRP CURE IT base coat. Usually, 2 or 3 mixes required. Working time about 30 min, so we had to work fast to minimise wastage of materials. For small and medium-size roof two builders are advisable to carry on the task.

5. Fibreglass Topcoat and windows installation


apply GRP topcoat TW2


Velux windows installation Twickenham

  • Topcoat GRP fibreglass
  • Rainwater Gutter pipes
  • Velux windows glass installation
  • Lead Flashing and apply Patination oil
  • Plasterboard fitting on the ceiling
  • Spotlights installation
  • Plastering and making good
  • Painting ceiling, walls and woodwork