Attic Completion Work - Course: Timberwork techniques. Instruction examples for practical vocational training (Institut für Berufliche Entwicklung, 39 p.)
 (introduction...) Preliminary Remarks Instruction Example 2.1.: Making Openings for Roof Superstructures in Existing Roofing Instruction Example 2.2.: Making a Rafter Trimming Instruction Example 2.3.: Making the Opening for the Roof Window to be Built in Instruction Example 2.4.: Joining of the Parapet Transom Instruction Example 2.5.: Joining of the Window Posts Instruction Example 2.6.: Joining of the Lintel Transom Instruction Example 2.7.: Joining of the String Transoms and Roof Rafters

### Instruction Example 2.1.: Making Openings for Roof Superstructures in Existing Roofing

This instruction example explains how to saw out the openings for the roof window to be built in the existing roofing.

Constructional details

- Gable roof as purlin roof with triple upright truss.
- Eaves angle: 45 degrees.
- Rafter distance: 800 mm.
- Roofing consisting of 24 mm thick boards with slating.
- Scaffolding is available at the facade.

Figure

Hand tools

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

Measuring and testing means

Folding rule

Auxiliary accessories

Marking pencil, roofers' scaffolding, facade scaffolding, safety belt with catch rope

Necessary previous knowledge

Measuring, scribing, boring, sawing, functions of angles, reading of tabular values, reading of drawings

Explanations to the working drawing

1 = area where the roofing is to be removed

 Sequence of operations Comments 1. Determine the sizes for the openings to be saw out and draw a hand sketch. See working drawing! 2. Check facade scaffolding for completeness and stability. Check covering of uprights for support.Check anchoring and bracing. 3. Measure-in and scribe on the existing roof face the lower horizontal limitation for removing the roof slates. Take the sizes from the hand sketch. Scribe with the marking pencil at one window only, starting from the centre of the roof window.Draw the scribed line at both sides beyond the trimmer rafters. 4. Measure-in and scribe the lateral limitation of the roof window opening. Measure from the centre of the roof window. Start scribing about 100 mm below the lower horizontal limitation and continue until about 300 mm upwards. 5. Remove the roof slates above the lower limitation line. Remove the roof slates so that they can be used again.The outer edge of the trimmer rafter must be free of slates. 6. Mount the roofer's scaffolding on the slate roof surface. Use scaffolding trestles with brushes. 7. Measure-in and scribe the upper horizontal limitation for removing the roof slates. Work on the roofer's scaffolding with safety belt only.Fix catch rope to ladder hooks. Draw scribed line at both sides beyond the trimmer rafters (see working drawing for sizes). 8. Remove the slates up to the upper horizontal limitation of the opening. Laterally the opening is limited by the trimmer rafters. 9. Produce a borehole at the inside of the trimmer rafters below the upper limitation line. Use a 20 mm diameter bit to enable the compass saw to start. If possible, bore near a roof board joint. 10. Saw out the first board with the compass saw. Guide the compass saw blade along the inside face of the trimmer rafter.Don't let the sawn-out board fall into the attic - danger of accidents! 11. Saw out the roof boards up to the lower horizontal limitation using a pad saw and then a hand saw. Guide the saw blade along the inside face of the trimmer rafter. 12. Remove the roofers' scaffolding. 13. Measure-in and scribe the limitation for the next opening. Measure from the centre of the first roof window.Repeat steps 3. through 12.

Roof Superstructures