Instructions for attic conversion


Since the Energy Saving Ordinance in 2011 mandatorily stipulates a deadline for insulating residential floors to attic floors, but these come into effect under different conditions, loft conversion has become very popular. Finally, the roof insulation can be combined with an expansion. Following you will receive instructions for attic conversion.

Connect the roof insulation with the loft conversion

As early as 2009, the legislature stipulated in the Energy Saving Ordinance EnEV that all roofs should be insulated by the end of 2011. Due to numerous exceptions, the roof insulation was not due in one fell swoop. Instead, many roofs need to be insulated only when certain events occur.

  • heritage
  • purchase
  • modification

Many property owners take this as an opportunity to combine the roof insulation with a loft extension, after all, the trend is towards more living space. However, the roof structures must also be distinguished.

  • cold roof
  • warm roof

The instructions for attic conversion refer to a warm roof

While roofs have been designed as ventilated cold roofs for decades, the warm roof is only beginning to take effect today. However, in the roof insulation often takes place a change to the warm roof. Therefore, the following instructions for the loft conversion also refers to the expansion, if a warm roof is available.

Step by step instructions for loft conversion

  • Insulating material such as clamping felt
  • special adhesive tape for staples
  • vapor barrier
  • Adhesive tape and adhesive (cartridge) for vapor barrier
  • Electrical installation materials
  • Plasterboard
  • putty
  • Drywall screws
  • Cutter knife
  • Metal profile as a cutting aid
  • stapler
  • silicone syringe
  • Hole saw for drilling machine
  • drilling machine
  • Cordless Screwdriver
  • trowel
  • Spatula bowl or bucket
  • Site manager or easel

1. Preparatory work

First, check the rafter thickness. One of the EnEV appropriate thermal insulation must have a thickness of 18 to 20 cm. If your rafters do not reach this strength, you can slat the rafters.

2. Damp with the clamping felt

Always cut the insulation felt slightly larger than the dimensions from one spar to the next. The insulating mats must namely be used completely joint-free.

3. Attach the tacking tape

Now stick the special adhesive tape for the staple clamps along the rafters. This tape prevents the vapor barrier foil from cracking or leaking later.

4. Mount the vapor barrier

Now lay the individual lanes of the vapor barrier. At the ends (ridge ends) let the film survive 5 to 10 cm. Overlaps should be 10 to 15 cm. Then staple the foil firmly.

At the overlaps you glue the film airtight with the appropriate adhesive tape. Also at penetrations you must glue the vapor barrier airtight. At the ridge ends, fold the foil inwards. Now spray approx. 0.8 cm thick beads from the sealing adhesive into the inner corner. Then put the vapor barrier over it again. After drying, you can cut off the supernatant.

5. Fasten the gypsum boards

You can now screw the gypsum boards onto the rafters or the roof battens attached to them. The screws should be about 80 to 100 cm apart, depending on their size. Be sure to bolt the joint edges of the gypsum boards to shock. If you had to cut off the lowered joint of the plates, you must chamfer the plates to get a groove again.

6. Fill the plasterboard with sand and grind

Now you can fill in and sand the plasterboard. Depending on the surface quality you need, you may have to fill and sand several times.

Tips & Tricks

If you need to attach battens to the rafters to achieve the required insulation thickness, you can also attach them to the rafters. The subsequent insulation is then also on the rafters. This way you avoid thermal bridges.

The sanding of plasterboard is demanding even for experienced craftsmen. In the house journal you will find corresponding instructions, for example under plasterboard.


Video Board: DIY Loft conversion, (saved £16000) and added an extra bed room.