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Leaving Cert Construction Studies: Thermal bridges & condensation

How often Thermal bridges & condensation comes up on the Construction Studies papers, every year it was asked, and questions to try.

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

OL Asked on 2 of the last 9 Ordinary Level papers, most recently in 2017.

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.

Thermal bridges & condensation, Higher Level(7 marks)

Quick ones on Thermal bridges & condensation.

(a)What is a thermal bridge?
  1. A gap left at the eaves for roof ventilation
  2. A part of the envelope with much higher heat loss
  3. A timber walkway laid across a flat roof
(b)Why is the vapour control layer placed on the warm side?
  1. Stops radon entering through the walls
  2. Keeps rain out of the wall from outside
  3. Stops vapour reaching cold layers and condensing
(c)Swapping the VCL and breather membrane positions causes?
  1. Interstitial condensation inside the wall
  2. A better U-value for the whole wall
  3. Faster drying of the wall after heavy rain
Show the answers

(a) A part of the envelope with much higher heat loss

(b) Stops vapour reaching cold layers and condensing

(c) Interstitial condensation inside the wall

Your turn: Higher Level questions on Thermal bridges & condensation.

Higher Level

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

Every paper, year by year

YearWhere it came up
2025Not asked
2024Not asked
2023Q5
2022Q1
2021Q1, Q5
2019Q9
2018Not asked
2017Not asked
2016Not asked

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

More Thermal bridges & condensation questions

Thermal bridges & condensation, 2 marks

What is relative humidity?

  1. The weight of water held in each cubic metre of the wall
  2. The temperature at which ice forms on glass
  3. Vapour held as a % of the maximum at that temperature
Show the answer

Vapour held as a % of the maximum at that temperature

Warm air can hold more water vapour than cold air, so the same moisture gives a lower RH in a warm room and a higher RH beside a cold surface.

Thermal bridges & condensation, 3 marks

Moist room air cools as it meets a cold window. What happens to its relative humidity?

  1. It stays exactly the same as before
  2. It rises until the dew point is reached
  3. It falls to zero as the water vapour cools
Show the answer

It rises until the dew point is reached

Cooling does not remove vapour but lowers how much the air can hold. At 100% RH, the dew point, water condenses on the glass.

Thermal bridges & condensation, 2 marks

Best overall way to cut condensation risk in a house?

  1. Cut moisture at source, ventilate, keep surfaces warm
  2. Turn the heating off at night so the air dries out
  3. Seal every vent and window to keep damp out
Show the answer

Cut moisture at source, ventilate, keep surfaces warm

Extract fans at cookers and showers, drying clothes outside, steady heating and good insulation all work together. Sealing vents traps the vapour inside.

Ordinary Level

Asked on 2 of the last 9 Ordinary Level papers, most recently in 2017.

Every paper, year by year

YearWhere it came up
2025Not asked
2024Not asked
2023Not asked
2022Not asked
2021Not asked
2019Not asked
2018Not asked
2017Q5
2016Q1, Q8d

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

More Thermal bridges & condensation questions

Thermal bridges & condensation, 3 marks

A common place for a thermal bridge in a house?

  1. In the middle of a fully insulated wall
  2. In the centre of a triple-glazed pane
  3. Where the ground floor meets the external wall
Show the answer

Where the ground floor meets the external wall

Junctions are the weak spots. At a floor edge, lintel or window reveal, the insulation layers may not meet, so heat escapes there faster.

Thermal bridges & condensation, 2 marks

What causes condensation on a wall or window?

  1. Heat from a radiator on the wall
  2. Warm, moist air meeting a cold surface
  3. Rain soaking in through the wall
Show the answer

Warm, moist air meeting a cold surface

Cold surfaces cool the air next to them. Cool air holds less water vapour, so the extra moisture turns to droplets on the glass or wall.

Thermal bridges & condensation, 3 marks

Best way to reduce condensation in a bathroom?

  1. An extract fan to remove the moist air
  2. Keep the window closed all the time
  3. Turn off the heating after a shower
Show the answer

An extract fan to remove the moist air

Showers fill the air with water vapour. An extract fan removes it at the source before it can settle on cold surfaces and cause mould.

Other Construction Studies topics

All of Leaving Cert Construction Studies