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Leaving Cert Construction Studies: Timber upper floors

How often Timber upper floors comes up on the Construction Studies papers, every year it was asked, and questions to try.

HL Asked on 2 of the last 9 Higher Level papers, most recently in 2024.

OL Asked on 4 of the last 9 Ordinary Level papers, most recently in 2023.

June 2028 is the first exam on the new Construction Studies course. These come from the 2016–2025 papers, so read them as a guide.

Timber upper floors, Higher Level(6 marks)

Quick ones on Timber upper floors.

(a)Purpose of herringbone strutting between floor joists?
  1. Supports the plasterboard ceiling boards
  2. Stiffens the joists and stops them twisting
  3. Adds sound insulation between the floors
(b)Joists around a stairwell opening are?
  1. Notched and bolted to the stair string
  2. Single joists at wider centres
  3. Doubled trimmer and trimming joists
(c)Typical upper-floor joist size and spacing in a house?
  1. 200–225 × 50 mm at 400 mm centres
  2. 300 × 100 mm at 900 mm centres
  3. 100 × 50 mm at 1200 mm centres
Show the answers

(a) Stiffens the joists and stops them twisting

(b) Doubled trimmer and trimming joists

(c) 200–225 × 50 mm at 400 mm centres

Your turn: Higher Level questions on Timber upper floors.

Higher Level

Asked on 2 of the last 9 Higher Level papers, most recently in 2024.

Every paper, year by year

YearWhere it came up
2025Not asked
2024Q7
2023Not asked
2022Not asked
2021Not asked
2019Not asked
2018Q7
2017Not asked
2016Not asked

Links open the State Examinations Commission’s paper for that year.

More Timber upper floors questions

Timber upper floors, 3 marks

Why are floor joists set on edge rather than laid flat?

  1. Floorboards fit better on a narrow edge
  2. It saves headroom
  3. Depth gives far more strength and stiffness
Show the answer

Depth gives far more strength and stiffness

Stiffness rises with the cube of depth, so doubling the depth makes a joist about eight times stiffer. Laid flat, the same timber would sag badly.

Timber upper floors, 2 marks

Why are tongue-and-groove boards used for floor decks?

  1. They need no fixings
  2. The boards lock together and share loads
  3. They let the floor breathe through the joints
Show the answer

The boards lock together and share loads

Each tongue sits in the next board's groove, so boards cannot move against each other. This stops edges lipping, cuts squeaks and stiffens the floor.

Ordinary Level

Asked on 4 of the last 9 Ordinary Level papers, most recently in 2023.

Every paper, year by year

YearWhere it came up
2025Not asked
2024Not asked
2023Q1
2022Not asked
2021Q8a
2019Q5
2018Not asked
2017Q7, Q8h
2016Not asked

Links open the State Examinations Commission’s paper for that year.

More Timber upper floors questions

Timber upper floors, 2 marks

What are joist hangers?

  1. Straps that stop the roof trusses lifting in the wind
  2. Timber pieces fixed between the studs
  3. Steel brackets that support joist ends at a wall
Show the answer

Steel brackets that support joist ends at a wall

Instead of building the joist end into the block wall, a steel hanger holds it. This keeps the joist dry and helps keep the wall airtight.

Timber upper floors, 3 marks

Why is herringbone strutting fitted between floor joists?

  1. To hold up the insulation between the joists
  2. To stiffen the joists and stop them twisting
  3. To carry electrical cables across the floor
Show the answer

To stiffen the joists and stop them twisting

Pairs of small timbers are fixed diagonally between joists. They make the joists act together, so the floor is stiffer and bounces less.

Timber upper floors, 3 marks

Why is a trimmer joist used at a stair opening?

  1. It carries the ends of the joists cut short
  2. It makes the floor soundproof above
  3. It supports the handrail at the top
Show the answer

It carries the ends of the joists cut short

Joists that would cross the stairwell are cut short. The trimmer, usually doubled, runs across to pick up their ends and passes the load to the trimming joists.

Other Construction Studies topics

All of Leaving Cert Construction Studies