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close this bookAttic Completion Work - Course: Timberwork Techniques. Instruction Examples for Practical Vocational Training
View the document(introduction...)
View the documentPreliminary Remarks
View the documentInstruction Example 2.1.: Making Openings for Roof Superstructures in Existing Roofing
View the documentInstruction Example 2.2.: Making a Rafter Trimming
View the documentInstruction Example 2.3.: Making the Opening for the Roof Window to be Built in
View the documentInstruction Example 2.4.: Joining of the Parapet Transom
View the documentInstruction Example 2.5.: Joining of the Window Posts
View the documentInstruction Example 2.6.: Joining of the Lintel Transom
View the documentInstruction Example 2.7.: Joining of the String Transoms and Roof Rafters

Instruction Example 2.3.: Making the Opening for the Roof Window to be Built in

This instruction example teaches how to make the opening in the existing roofing for the upright roof window with lean-to dormer roof to be built in.

Constructional details

- Gable roof as valley-beam (collar-beam) roof.
- Eaves angle: 45 degrees.
- Rafter distance: 820 mm.
- Upper edge of head rail: 2200 mm.
- Roofing consisting of 24 mm thick roof boards and two layers of roofing felt.
- Scaffolding is available at the facade.


Hand tools

Hammer, hand saw, compass saw, pad saw, bit brace, insert bit of 20 mm diameter, carpenter's pincers, knife

Measuring and testing means

Folding rule, water-level

Auxiliary accessories

Marking pencil, battens of about 800 mm and 2300 mm length, straight-edge, safety belt with catch rope, 3.1/70 nails, ladder battens - 10 pcs.

Necessary previous knowledge

Measuring, plumbing, scribing, boring, sawing, reading of drawings

Sequence of operations


1. Make available the necessary tools and materials.

Secure tools and materials against falling down from the roof.

2. Saw to length short batten to 750 mm and long batten to 2200 mm.

Saw the two battens at right angles!

3. Find out in the attic the rafters where to build in the roof superstructure.

Take size from the drawing!

4. Place short batten perpendicularly on the floor leaning to the rafter on top and shift it towards the eaves angle.

Use water-level! Place water-level to ensure perpendicularity when shifting the batten towards the eaves angle! Shift batten up to the roof bearding!

5. Scribe marking-out line on roof boarding.

6. Scribe height line on opposite rafter.

Repeat steps 4. and 5!

7. Place nail on scribed line and drive it through the roofing from the inside to the outside.

Make sure that the nail is long enough to penetrate at the outside roofing!
Place nail as close at the rafter as possible.
Repeat this at the neighbouring rafter.

8. Place long batten perpendicularly on the floor and scribe upper limitation of the opening.

Similarly to steps 4. through 7.

9. Check facade scaffolding including safety measures for completeness and stability.

Check anchoring or bracing and upright covering support.
Check safety fence, particularly for foot board!

10. Locate straight-edge at driven-through nails and scribe lower limitation of opening.

Locate the straight-edge so as to scribe the limitation of the opening greater by the straightedge width. Use marking pencil.

11. Locate straight-edge for lateral limitation at the driven-through nails and drive in tack-nail.

Drive in tack-nail to prevent the straight-edge from slipping off! Do not drive in the nail completely because it has to be pulled out again!

12. Nail ladder battens onto roofing at a distance of about 500 mm.

Nail on ladder battens outside the opening to be made at a distance of about 100 mm from the

tacked straight-edge!
Nail length should equal at least 2 times the thickness of the ladder batten!
Use the safety belt and fix the catch rope to the ladder hooks!

13. Scribe lateral limitation of the opening.

Scribe greater by the straight-edge width!

14. Loosen and remove straight-edge.

Pull out nail with hammer pane!
Pull out nail just as much as to permit the straightedge to be removed!

15. Locate straight-edge at opposite side and scribe lateral limitation.

Proceed similarly to steps 11. through 14.

16. Drive nails for opening limitation back.

Just drive back nails, do not pull them out!

17. Loosen and remove roofing felt between the scribed marking-out lines.

Guide the knife along the scribed lines and cut the roofing felt through!
Pull out with pincers any felt nails left in the roof boarding!
Do not throw the removed roofing felt from the scaffolding!

18. Bore a hole at the inside of the roof rafter below the upper limitation nail.

Use 20 mm diameter bit to enable the compass saw to start!
Bore close to a roof board joint, if possible!
Do not bore into the driven-in nail! Use the safety belt!

19. Bore a hole at the neighbouring roof rafter.

Repeat step 18.!

20. Saw out the first board using the compass saw.

Guide compass saw blade along the inside face of the rafter!
Do not let the sawn-out board fall into the attic!

21. Saw out the roof boards up to the lower horizontal limitation of the opening using a pad saw and hand saw.

Guide the saw blade along the inside face of the rafter!
Do not let the boards fall into the attic!

22. Clear the working place.

Store the sawn-out boards in the attic. Pull out driven-in or left roofing felt nails!
Remove the cut out roofing felt from the scaffolding but do not throw it off!
Do not remove the ladder battens, they can be used for building in the upright roof window!

Opening in roof window to be built in