Building Pathology Flashcards
What are typical defects associated with Georgian Properties?
Damp
Roof Defects
Walls
Foundations
What are the common defects to a Georgian Building Wall?
Penetrating damp due to single skin wall
Frost Damage
Sulphate Attack
Spalling
What are the typical defects to a Georgian Building Roof?
Roof spread
Roof Sag
Defective slate tiles
Can you name steel related defects?
Rust
Corrosion
displacement
What are the main components in a Victorian Roof?
(top down) Slates or tiles Underfelt (in late Vic era) Ride plat Rafters Purlin Ceiling Joists Wall Plate
What are the typical defects of a Victorian Roof?
Roof sag roof spread rotten timbers delaminating slates defective valleys defective flashings
Can you explain interstitial condensation and where it can be found?
Condensation which occurs between building elements
Can be found in cavities
Cold roofs
Defective double glazing
On Sadler House what kind of sealant did you recommend?
This was specified in accordance with the Weber light weight render system.
What are the tell tale signs of rising damp?
Horizontal tide marks, peeling paint or plaster
What remedial works did you specify for 47 David Place?
DPC was shattered and i specified an injected DPC
Down pipe discharging onto paved area where damp was located, this was relocated.
What remedial works did you specify for the external cracked areas to 47 David Place?
Just under 5mm i specified pointing up with lime mortar.
What are the common victorian walls?
solid or cavity
How would you identify if the victorian wall has a cavity?
This was be approx 20-30 mm thicker than a 230mm solid brick wall.
Can you inject insulation into a Victorian
No the gap would need to be at least 50mm.
What are the three common defects to masonry in Vic buildings?
spalling
frost
sulphate attack
What is the tell tale sign of frost damage in brick work?
spalling surface
How would you repair spalling brickwork?
Depending on severity, remove brick with all saw and reinsert the other way around.
Rebuild with lime mortar and pigments
If not reparable replace with appropriate porous brick.
Why is remediating Victorian walls with lime important
lime is breathable whereas modern cement is not
What is the typical defect at the end of a Victorian terrace?
leaning
Why is leaning a typical structural defect to victorian buildings at the end of a terrace?
Because the side wall often has little restraint.
What is the typical construction of a Victorian Building Foundation footing?
This would be a stepped footing.
Relating to Victorian Buildings describe a stepped footing?
Trenches are approx 450mm deep and the foundations are layed with bricked starting 700mm in width decreasing as they extend up.
Describe load bearing in some common soil types? (four types)
Chalk and rock are firmest.
Sand and gravel have good characteristics
Peat is poor
Clay is good but subject to shrinkage and swelling.
Describe the process of shrinking and swelling to clay soil?
Wet periods clay swells, whereas in dry periods clay shrinks and cracks.
What is the difference between subsidence and differential settlement?
Subsidence is caused by a change in the soil load bearing capacity or differential movement due to the varying depth of foundations.
Settlement is when the building moves as a whole when first built.
What is the most common cause of subsidence?
Tree related.
What is the problem with removing a tree which is close to a building?
The sub-strata may swell and cause heave.
What are the options for managing a tree which causes high amount of shrinkage?
Pollarding or Heavy pruning.
What is the problem with underpinning a terrace block of Victorian Buildings?
This is likely to move the subsidence to another area. An alternative option would be to pollard the area, if possible.
What are the common roofs types in victorian buildings?
Pitched, butterfly and lean too.
What is the sequence of operation of a pitched roof (detail)?
Top down
slates/tiles
underfelt.
The roof structure is ridge plate rafters battens purlin strut binder joists wall plate.
What is the risk of insulating the roof in victorian buildings?
Reduces breathability and increases the likelihood of rot and mould.
If recommending a roof covering to a victorian building what would you consider?
Structure. Victorian buildings roof timbers were installed sparingly which works for light slates, however if heavy concrete tiles are installed it will likely lead to roof sagging.
What makes Welsh slate identifiable?
It has a grey purple hue.
What defects are common at flashings?
Concrete fillets spall and lead to ingress. Vegetation growth.
Defective lead detailing
What would you suspect for a sagging roofs?
Poorly cut rafters, purlin deflection.
How would you remediate week roof timbers?
Strengthen roof timbers.
What defect would you expect for roof spread?
I would expect the ceiling joists to be inadequately fixed to the walls.
What would you expect for a leaking victorian roof with slates?
slipped, missing or damaged slates.
How would you go about remediating ingress to a victorian roof with slates?
Assess how many slates are defective. If only a few require remediating I would recommend replacement of those. If there is widespread delimitation blistering I would recommend whole sale replacement.
Explain the facade and ingress failure at Sadler House?
No primary joint sealants at window.
External Render had significant spalling and cracking.
What were the cladding defects on Windward House?
The cladding showed signs of sea/air borne pollutants
The actual cladding was not in poor condition however it lacked routine maintenance.
What type of insulation is at Windward House prior to the work?
This was a Expanded polystyrene.
What insulation type did you consider for Windward House and Liberation House?
This was a phenolic system.
What are the disadvantages and advantages of a phenolic insulation system?
Strength and Structure Heat resistance Moisture resistance Fire performance Recycling
Disadvantage is that it is more expensive
What is the advantage of a tapered insulation system?
Pre determined falls are achieved via off site manufacturing.
What are the four types of damp?
Condensation
Rising Damp
Penetrating damp
Flooding
Explain condensation?
water vapour changes to liquid
When hot air touches a cold material it reaches its saturation point and turns to moisture