Module 3 Hmk Quiz Q10

[Ben Gorman]

Here is Question 10, along with my thoughts about how to answer it. I don’t know whether or not I have the correct answer. I would be really interested in your comments.

Be aware that the online quiz tends to change the order of the answer options.

**** QUIZ QUESTION ****

Quiz question 10
Looking forward to module 5 where we will be looking at how to improve all the elements of a building, which of the options below would likely to offer the lowest risk, most reliable and easiest strategy to improve the ground floor whilst incorporating good levels of insulation and airtightness, whilst minimising thermal bridging and thermal bypass?
1. Cut back rotting joist ends, bolt new timbers to side of joist inserting into newly formed holes in brickwork wrapping ends in damp proof plastic. Create access to floor space and insert insulation between joists by crawling beneath. Attach a wind proof vapour open membrane to the underside of joists tape butt joints and to the walls
2. Repair joist ends as above, render with a weak sand and cement parge coat on bare brickwork between joists and behind skirting. Take up all the floorboards and lay the wind tight vapour membrane up and over the joists taping the butt joints and to the parged wall. Lay mineral insulation between the joists and re-lay a glued or chipboard floor
3. Take out timber floor completely, raise ground level with hardcore, lay sand blinding, damp proof membrane, rigid insulation and pour concrete slab. Ensure a insulation upstand around the slab edge to minimise thermal bridge

**** MY THOUGHTS ****

It would be good to know if cost is being considered in this example, as Bill mentioned during the tutorial. If there is sufficient money in the budget maybe 3 would be best. Can anyone clarify the difference between the other two options?

[Tim Gilbert]

Hi Ben,

To me the main difference between 1 & 2 is that 2 is including some effort to reduce the dampness under the floor. Neither of the options address the blocked vent, paving sloping to the wall, inserting DPC at the sleeper walls etc. Therefore the only complete answer is 3.

Tim

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