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Subjects · Leaving Cert Construction Studies

Leaving Cert Construction Studies: External walls

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

HL Asked on 3 of the last 9 Higher Level papers, most recently in 2025.

OL Asked on 6 of the last 9 Ordinary Level papers, most recently in 2025. most years

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.

External walls, Higher Level(7 marks)

Quick ones on External walls.

(a)Layers of a full-fill block cavity wall, outside to inside?
  1. Render, filled cavity, outer leaf, inner leaf, plaster
  2. Render, outer leaf, filled cavity, inner leaf, plaster
  3. Plaster, outer leaf, filled cavity, inner leaf, render
(b)Standard spacing of wall ties in a cavity wall?
  1. 1800 mm horizontally, 900 mm vertically
  2. 450 mm horizontally, 900 mm vertically
  3. 900 mm horizontally, 450 mm vertically
(c)Why does a wall tie have a drip in the middle?
  1. So water cannot cross the cavity to the inner leaf
  2. To let the tie flex as the leaves move in a storm
  3. To grip the insulation batts against the inner leaf
Show the answers

(a) Render, outer leaf, filled cavity, inner leaf, plaster

(b) 900 mm horizontally, 450 mm vertically

(c) So water cannot cross the cavity to the inner leaf

Your turn: Higher Level questions on External walls.

Higher Level

Asked on 3 of the last 9 Higher Level papers, most recently in 2025.

Every paper, year by year

YearWhere it came up
2025Q4
2024Not asked
2023Not asked
2022Not asked
2021Not asked
2019Q1
2018Not asked
2017Q4
2016Not asked

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

More External walls questions

External walls, 2 marks

Role of the OSB or plywood sheathing on a timber frame?

  1. It forms the breather membrane
  2. It is the base for the plaster skim
  3. Braces the frame against racking
Show the answer

Braces the frame against racking

Racking is the sideways push of wind that turns a rectangle into a parallelogram. Sheathing nailed to the studs makes each wall panel rigid.

External walls, 2 marks

Why does a timber-frame sole plate sit on a DPC?

  1. To form the airtight layer
  2. To stop moisture rising into the timber
  3. To fix the frame to the foundation
Show the answer

To stop moisture rising into the timber

Masonry and concrete below hold moisture. A DPC under the treated sole plate keeps it dry so it cannot rot; the frame is fixed down separately.

External walls, 3 marks

Why must the wall DPC be at least 150 mm above outside ground level?

  1. So splashing rain cannot bypass it
  2. To leave room for the skirting
  3. So radon can escape under it
Show the answer

So splashing rain cannot bypass it

Rain bouncing off paving or soil wets the lowest courses of the wall. Keeping the DPC 150 mm up stops that water rising into the wall above and the floor.

Ordinary Level

Asked on 6 of the last 9 Ordinary Level papers, most recently in 2025. most years

Every paper, year by year

YearWhere it came up
2025Q7, Q8f
2024Q8h, Q9
2023Q1
2022Q8g
2021Not asked
2019Q4
2018Not asked
2017Q8d, Q8i
2016Not asked

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

More External walls questions

External walls, 2 marks

What do wall ties do in a cavity wall?

  1. Stop radon rising up the wall
  2. Hold the insulation to the plaster
  3. Tie the inner and outer leaves together
Show the answer

Tie the inner and outer leaves together

The two leaves of block are separated by the cavity. Wall ties bridge the gap so both leaves act together and the outer leaf cannot bulge or fall.

External walls, 2 marks

Purpose of a damp-proof course (DPC) in a wall?

  1. To support the floor joists
  2. To stop moisture rising up the wall
  3. To let the wall breathe out water vapour
Show the answer

To stop moisture rising up the wall

Wet ground soaks up into blockwork like a sponge. A DPC is a waterproof layer built into the wall above ground level to block this rising damp.

External walls, 3 marks

Why are wall ties made of stainless steel?

  1. They will not rust in the damp cavity
  2. Stainless steel is a good insulator
  3. They are cheaper than plastic
Show the answer

They will not rust in the damp cavity

The cavity can be damp. Ordinary steel would rust, expand and crack the wall, and could fail. Stainless steel lasts the life of the building.

Other Construction Studies topics

All of Leaving Cert Construction Studies