Cover Image
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 2.6.: Joining of the Lintel Transom

This instruction example teaches how to join the lintel transom for an upright roof window with lean-to dormer roof.

Constructional details

- The opening in the roofing has already been made.
- Window posts are to be joined with a corner tenon.
- Cross sections of timbers are shown in the workshop drawing on page 7.
- Lintel transom is cut to a length of 950 mm.


Hand tools


Measuring and testing means

Folding rule

Auxiliary accessories

Trestles (one ell), pencil, marking gauge, workshop drawing, engineer's square

Necessary previous knowledge

Measuring, scribing, angling, use of marking-out marks, reading of drawings

Explanations to the working drawing

The figures 2 to 7 represent the steps as per sequence of operations.
I joining side, II bottom side of lintel transom. III side opposite to joining side, IV top side of lintel transom

Sequence of operations


1. Prepare the working place, erect the trestles with the correct distance.

Check the trestles for firm standing and stability!
Store timbers to be joined, which are not used now, outside the working area.

2. Put lintel transom on trestles, decide on joining side and mark with marking-out mark.

Joining side "I" shall have an even face!
Any slight camber is to be used as top side of the lintel transom and to be marked with "IV"!

3. Scribe section line at left end of lintel transom, angle onto all four faces and mark with marking-out mark.

Go only as far to the right as to permit a right-angle section to be produced! Use engineer's square for scribing! Place lintel transom so that face marked "II" is on top again!

4. Measure-in length of lintel transom from section line towards the right, angle onto all four faces and mark with marking-out mark.

Place folding rule exactly and in parallel! Use engineer's square for scribing!

5. Measure-in and scribe window post width, starting from left and right section line and measuring towards the centre.

For window post widths see Instruction Example 2.4.!

6. Measure-in and scribe the comer tenon width from the two scribed lines towards the ends of the lintel transom.

Scribed line must be in parallel with scribed line of step 5. above!

7. Scribe corner tenon.

Use marking gauge and place sharp pencil exactly at marking gauge end face! Do not cant marking gauge when scribing!
Pass marking gauge along joining side for the two scribed lines!

8. Chisel out the mortise, cut lintel transom to length, take it off the trestles and store it outside the working area.

Joining of the lintel transom