Building Pathology 2 Flashcards
Tell me about the cause and mechanics of one type of failure.
Penetrating dampness in a traditional solid stone property with spalling stonework. The property has been repointed using a cement pointing and the stonework is starting to crumble in areas.
Traditionally the property would be pointed with a lime based mortar (porous) which allows moisture in and out of the wall through evaporation. The cement is a non porous material and as its a rigid material is susceptible to cracking therefore moisture can entre but cannot escape in the same way. This has lead to water penetration with dampness visible internally and spalling brickwork externally.
Tell me about the defects/issues you have identified from a building inspection.
Brigshaw Lane-
Impervious masonry paint on a solid brick wall that had been pointed with cement mortar. Both of which are not traditionally used in this type of construction.
Vegetation growing in the gutters and perished window sealant both causing water penetration.
Tell me about the relationship between site observations and the diagnoses of failure in building fabric.
Site observation allow us to visually inspect the building and each element of the property in a systematic fashion and this allows us to spot any defects and follow the trail of suspicion in order to diagnose why a certain building fabric has failed. I.e. dampness around chimney breast internally could be caused by defective flashing around the chimney stack externally.
Tell me about a type of specialist inspection you are aware of to diagnose and explain building fabric failure.
Drainage inspection in a Victorian property with clay pipes:
Clay pipes are more susceptible to cracking due to root damage or ground movement.
Noted cracking to boundary wall and large Shrub and tree next to the wall and inspection chamber. Furthermore, the hardstandings had cracked and and deteriorated. I found cracking to the property wall near the soil vent pipe. When I lifted the inspection chamber I could see a blockage in the chamber, therefore I recommended further investigation in the form of a CCTV report by a drainage specialist.
The cracked pipe had caused the ground/soil to move and affect the boundary wall, hardstanding and property wall.
Tell me about a report/survey you have provided to a client and the process you undertook to provide it.
Moseley wood View
Carried out pre-inspection due diligence checks and desktop research: EPC, flood risk, soil composition, street view. radon, coal mining, planning searches, floor and site plans.
I arrived at the property and inspected the surroundings including the boundaries, hardstandings, foliage, drains, pipework and outbuildings.
I then inspected the external elevations from chimney down to ground level. Then I inspected the interior starting on ground floor noting each area from ceiling down to floor level. I finally inspect the services and roof void.
I took detailed site notes, photos, site and floor plan including measurements and notations.
What issues did you identify?
I noted the ground level externally covered the airbricks to the extension and there was deterioration to the floorboards in the utility room.
What condition ratings did you apply?
CR3 with further investigation to inspect the underfloor void by a damp and timber specialist.
What reasoned advice did you provide as a result?
I advised that the ground levels were reduced to improve ventilation of the subfloor areas. I also advised that the flooring to part of the utility room would need to be replaced due to deterioration and this may include the replacing or repair of some floor joists.
I recommended further investigation of the subfloor by a damp and timber specialist as I was unable to lift the floorboards and see underneath to confirm the full extent of the damage underfloor.
If you provided a valuation as part of the instruction, how did the defect affect this?
If I did a valuation as part of the level 3 survey this defect would have had a negative impact on the value. However without known the full extent of the damage I could not obtain a cost figure, therefore I would put a retention on the valuation based on the further investigation which would include any remedial works that affect this area.
Tell me about an instance of when you have followed the trail.
Primley Park Avenue-
I noted cement render to the bottom of the bay window which bridged the DPC.
Furthermore, the ground level had been raised which also bridged the DPC. Internally the plaster around the bottom of the bay window was perished and flaking indicating penetrating dampness. This was confirmed with moisture meter readings.
I was able to deduce that the penetrating damp was caused by cracked cement render and ground level bridging the DPC. I recommended installing of a french drain to the base of the wall and the removal of the cement render.
Brigshaw Lane, how did you know that the paint was impervious?
There was a shine to the paint, its crumbled when touched and did not have a chalk like texture.
How did you carry out your moisture meter readings?
I carried out moisture meter readings to the skirting boards using the resistance meter and then measure moisture up to 1.5m high using the capacitance meter.
I carried on with this routine at regular interval around the property and around window and door openings.
How did you ascertain whether your moisture meter readings were accurate?
Make sure the moisture meter is calibrated before starting.
Sense check readings using a known measuring area.
Take multiple readings.
Follow the trail.
Mosely Wood View, tell me about the deterioration underfoot.
The some of the floorboards in the extension had deteriorated so badly that I was able to insert a screw driver through the floorboards. This was isolated to the section of the extension closest to the original property wall.
Tell me about your advice to the client.
I recommended that the ground level around the property is reduced to increase subfloor ventilation and help prevent further deterioration or wet rot. I also advised for further investigation by a damp and timber specialist to carry out a head and shoulders inspection of the subfloor void to check the full extent of the damage and provide quotes for any works required.
