Construction Technology and Environmental Services Flashcards
What is a Warm Flat Roof?
- Insulation above deck but below waterproofing layer.
- Lowers risk of condensation as void and ceiling are the same temperature as roof structure and deck.
What is a Cold Flat Roof?
- Insulation is placed at Ceiling Level.
- Cross ventilation is essential as this controls the risk of condensation.
- VCL reduces risk of condensation but is not 100% effective, hence need for ventilation.
What is an Inverted Flat Roof?
- Inverted flat roof is also a warm roof
- Insulation placed above the waterproofing layer
- No need for a VCL as interstitial condensation risk is eliminated.
- Insulation protects the waterproofing but needs ballast to hold it down.
At Cornwall St, Plymouth, did you consider alternative design solutions from a Cost/Time Perspective? What advice did you give the client?
- The preferred location for the staircase intersected a reinforced concrete beam.
- I advised of the likely need for a new structural column and beams, and pad foundation, if this option chosen.
- The alternative to site the stair parralell to the existing beam, was cheaper and less intrusive as it avoided need for foundations.
At Cornwall Street, what advice did you give the client re: Fire Safety?
- Void in floor was an intermediate floor.
- Typically intermediate floors in commerical use-classes require 60min fire protection, but depends on use-class, height of building and existence of sprinklers.
- Concrete floor typically do not require protection in order to achieve 60mins.
- As this was potentially a compartment wall separating 2 buildings, the requirement would be more stringent.
- See Part B Vol 2 page 126 for min periods of fire resistance
At Ilfracombe, what issues may have arisen if you had used a cemetitious render system?
- Because, as an older building, it relies on its breathability to keep out moisture - water absorbed by the fabric is allowed to evaporate back out.
- A cement render will inhibit evaporation.
- Cracks will appear in the cement render due to it being more rigid than the wall itself.
- Water will penetrate the cracks and become trapped, which can create serious structural issues.
At Ilfracombe, what ‘consultant’ input did you obtain?
- Advice was sought from an RICS chartered surveyor contact with conservation / heritage experience.
- This confirmed the issues with a lath and render system in this instance, even if a lime-render was used, due to the likelihood of cracks due to movement in the wall.
- The silicone based masonry paint contains silicone resins that are water repellant and highly breathable.
At Ilfracombe, what advice did you offer the client regarding maintenance?
- That the paint would need to be reapplied at regular intervals, especially as the surface was uneven, irregular and porous.
- The the internal face of the wall would need to be monitoredfor changes in damp and provision made for breathability from internal face as well.
At Woodside, Bristol, How did you determine that ‘Renderoc’ was an appropriate material for the repairs?
- It’s characteristics are defined in the data sheet.
- It’s a fibre-reinforced concrete reinstatement mortar.
- Suitable for RC concrete.
- High-build characteristic makes it suitable for patch repairs - less layers needed.
On the Cornerhouse, Exmouth, how did you ensure the roof achieved the required U-Value?
- Using a Heat-Flow Meter and monitoring conditions on both sides of the element. Would have been additional expense but is there as an option.
- Using a Clerk of Works on site to ensure workmanship.
Can you name some of the advantages and disadvantages of Steel Structural Frames?
- Pros: Fast Construction, Easier Quality Control, Fewer Operatives on site, Bigger Spans, Higher Tensile Strength.
- Cons: High Embodied Carbon, Tight Tolerances, Long Lead Time, High Upfront Cost.
Can you name some of the advantages and disadvatages of Reinforced Concrete Frames?
- Pros: Thermal Mass Smoothes Out Temperature Fluctuations, Faster Lead-Time, Better in Compression, Lower Up-Front Costs, Fire Protection, Air-Tightness.
- Cons: Slower Build Time, Highly Skilled Labour, Health and Safety.
How did you balance your advice on traditional repair methods and Conservation of Fuel and Power (Part L)?
- Traditional (vapour open) construction, doesn’t align often with demands to energy efficiency which promotes air-tightness.
- Wood-fibre insulation batts applied beneath a breathable lime plaster.
- Secondary Glazing
- Looking at on-site energy generation - e.g. solar panels, bio-mass etc.
You’re upgrading the insulation on a flat roof with a concrete deck, and it is not possible to achieve the necessary falls. What solution could get around this?
- Building up the deck with firring strips, or tapered beams and ply to build up the levels.
- Tapered insulation to create falls to a series of channels.
At Cornwall str Plymouth you discuss installation of a new staircase. What parts of the approved documents needed to be considered for this project?
- Part A: Structure
- Part B: Fire Safety
- Part K: Collision, Impact and Falling
- Part M: Access to and Use of Buildings
