SOE - Core Competencies Flashcards
What are common causes/conditions of condensation?
Condensation is a common occurrence in homes and is caused by warm, moist air coming into contact with cold surfaces. This can happen for a number of reasons, including:
- Everyday activities: Many activities in the home, such as cooking, showering, washing clothes, and breathing, produce moisture.
- Inadequate ventilation: When there isn’t enough ventilation, moisture can build up.
- Poor insulation: Low levels, missing or incomplete insulation can create cold spots in the home.
- Single glazing: Single glazed windows can’t warm up, which can lead to condensation.
What are the effects of condensation, and how can you spot it?
Condensation can often be spotted most easily on windows, where water droplets form on the window pane. It is also common to see water droplets forming in other areas with cold surfaces and where ventilation is poor, such as the corners of the room or behind furniture. Long term condensation can also begin to caused damage to the finishes and building elements. It is also common for condensation to have a musty smell.
If the water droplets are not removed, this can develop into black mould, which can be harmful to health.
Advise on the differences between condensation and damp.
Condensation is a type of moisture that forms on cold surfaces when warm, humid air cools down, while dampness is a result of penetrating water through walls, floors, and ceilings.
Are you aware of any guidance from the RICS on damp and mould.
RICS produced a Joint Position Statement (JPS) on investigating moisture and its effects on traditional buildings. The JPS was created in collaboration with Historic England and the PCA.
Explain your understanding of the Joint Position Statement, September 2022.
The JPS is a framework to guide surveyors through the best practice for investigating moisture related defects in traditional buildings. It establishes surveyors needs for knowledge and competence in the following areas:
Understanding the building to create a holistic picture.
Understanding moisture.
Understand moisture related building defects.
How to carry out a condition assessment.
Diagnosis and recommendations.
Legal requirements such as BC, planning and other standards.
Report accurately to the client.
What are the limitations of a damp meter?
Electrical resistance meters are not accurate for measuring moisture in masonry. While they can be used to establish profiles, they are not quantitative, due to salts, free water and metal content.
What is thermal imaging and what can it tell you?
Surveyors use thermal imaging, also known as thermography, to identify defects and energy deficiencies in buildings. Thermal imaging generates images of objects by capturing the infrared radiation they emit and shows differences in energy absorption and loss. Thermal imaging is a non-invasive technique that can be used to detect; dampness, cold bridges, leaking underfloor heating pipework and heat loss.
What are the limitations of a thermal imaging camera?
Obtaining useful information depends to a large extent on the basic principles of heat transfer, so the conditions at the time of the survey need to be correct.
* constant internal temperature of 20–22C for at least 72 hours before inspection
* a minimum temperature differential of 10C, between internal and external.
* clear internal faces to external walls; note that if there is a void behind a surface you will not record any useful infrared emissions from that source
* internal doors left open to encourage even heating
* no windows or external doors left open, as this would encourage cold air ingress.
How do thermal imaging cameras help to identify damp defects?
In the context of damp detection, thermal imaging can be used to identify areas of moisture in a building. This is because as moisture is lost from a surface by evaporation, it cools that surface and, as a result, areas of damp will often appear cooler in a thermal image than the surrounding areas.
However, a cold surface does not always indicate dampness. Once thermal images find an area of interest, this area should be inspected using more traditional methods.
If you are planning to use a thermal imaging camera, how would you inform the client to adequately prepare?
I would inform them that the accuracy of the thermal imaging survey will, to a large extent depend on the conditions as the time of the survey, so they will need to prepare appropriately to ensure the following:
* There is a constant internal temperature of 20–22C for at least 72 hours before inspection.
* There is a minimum temperature differential of 10C, between internal and external areas.
* The internal faces to external walls are clear.
* The internal doors are left open to encourage even heating.
* No windows or external doors left open, as this would encourage cold air ingress.
What are the common causes for structural movement?
Subsidence. Settlement. Frost Heave. Ground Heave. Removal of trees. Sulphate attack. Lintel failure.
How can you identify structural movement?
Cracks in walls, ceilings, or foundations can indicate structural movement.
Cracks that are large and vertical, or diagonal and wider at the top, are especially significant. Cracks above doorways that form a step pattern, or that appear with uneven floors or sagging ceilings, are also a cause for concern.
Doors and windows sticking or not opening or closing properly.
Walls that bow, bulge, or lean outward.
Floors that appear uneven or slant.
Gaps between walls and ceilings or floors.
How do electric resistance meters (damp meters) work?
Pin or probe types work by measuring the electrical resistance between two probes or pins to determine the moisture content of a material.
Pinless meters are non-invasive meters detect moisture using conductance by either radio frequency or capacitance of a material. Its readings are helpful for quickly determining moisture presence in a space. They should be further investigated and confirmed by taking measurements with a pin-type meter.
What are the housing periods in the UK?
Georgian and Regency – 1714 – 1837.
Victorian and Edwardian – 1837 – 1901 / 1901 – 1914.
Post WW1 Housing – 1918 – 1939
Post WW2 Housing – 1945 – 1990’s
What are some common defects of Georgian, Regency, Victorian and Edwardian Houses?
Arch failure – with timber backed lintels.
Bonding failure between walls.
Condensation.
Drainages problems.
Inappropriate use of cement mortar.
Inadequate foundations.
Lack of DPC.
Over stressed joists.
Penetrating damp, causing wet or dry rot to timbers and joists.
Poorly ventilated ground floors.
Failure of roof coverings.
What are some common defects in Post-War housing (1918 – 1939 /1945 – 1990)?
Failure of wall ties
Sulphate attack in floors
Cracking caused by unconsolidated hardcore.
Rising damp in early concrete floors with missing DPM.
Undersized floor joists due to lack of materials.
Fungal attack on external wood due to poor quality of wood.
What are some common defects with sand and cement render and why?
Cracking and shrinking are probably the most common defects that I have come across. Cement render is more prone to cracking and shrinking because they are less flexible and are less likely to be able to withstand thermal or moisture changes, or movement of the substrate.
What are common defects with flat roofs and why?
Blistering.
Cracking/splitting.
Ponding water.
Defects at upstands, where two structures meet.
What are some common defects with pointing and why?
Occasionally, pointing mixes are installed that mortar that is too dense (i.e too much cement). This will not allow the brickwork to ‘breath’ adequately and it will shrink and crack, which allows water ingress.
What are some common defects with timber windows and why?
Rotting – windows can rot over time due to harsh weather conditions.
Warping – changes in temperature and humidity can lead to warping.
Snapped sash cords.
Peeling paint.
At Ditton Hill Road, what was the pattern of cracking that indicated there was an issue with the support mechanism over the double doors?
As the lintel was absent, there was no structure supporting the brickwork or load above, leading to settlement of the brickwork over the opening. This caused diagonal cracking in the masonry over the opening, which were wider at the top than the bottom.
Why did the lack of a lintel at Ditton Hill Road, lead to settlement cracking?
As there was no support to the structure above, so it settled, and cracks because visible in the mortar joints.
What alterations were required at Ditton Hill Road to rectify the lintel issue?
I advised the client that this was unsafe, and a new lintel would need to be installed immediately. This would require removing brickwork and installing props to support the masonry above the opening, so that a suitable lintel could be installed.
I advised that a structural engineer would be required to specify the lintel required.
How did you identify that there was wet rot within the loft space in Ditton Hill Road?
When I entered the loft area, I was initially hit with a damp musky smell. I noted that the timbers in and around the valley board were a far darker shade and the timber had a moisture content of around 50% when test with a pronged damp meter, suggesting that the timbers were suffering from continued wetting. All of which are characteristics of wet rot.
How did you know that the rot in Ditton Hill Road was wet rot and not dry rot?
The main indicator for me was the moisture reading, which was around 50%, and the timber was soft and wet. I know that the breading condition for wet rot is above 40%, whereas dry rot is above 20%.
The rot was also quite localised to the extremely damp timbers and had not spread very far. Dry rot is known for spreading via its mycelium. This was not apparent within the loft.
Describe the conditions for dry rot growth.
Dry rot, a fungal infection that can weaken a building’s structure, grows in the following conditions:
- Dry rot requires a source of moisture and a lack of ventilation.
- Spores germinate when they land on damp timber with a moisture content of over 20%.
- The ideal temperature for dry rot growth is around 22°C, with a maximum of around 26°C.
How had the lead detailing to the gutter and chimney stack failed at Ditton Hill Road, to allow such serious water ingress issues?
Our inspection showed that there was a concealed valley gutter to the butterfly roof. The lead detailing to the chimney stack, which extended through the gutter was defective and could be an easy point for water to enter the building fabric.
What is a butterfly roof and what are the negatives of this type of roof construction?
A butterfly roof is a V-shaped roof that’s made up of two pieces that angle upward on the outside and meet in a valley in the middle. It is almost like an inverted pitched roof.
Due to the pitch, it is difficult to access the central valley for maintenance, and it is often forgotten about as it cannot be easily seen.
How did you advise the client at Ditton Hill Road on how to rectify the wet rot issue?
To treat wet rot, you first need to find the cause of the penetrating water and eliminate it to remove the damp conditions.
Depending on the condition of timbers, they should either be treated fungicide to kill and remove the rot. If they are salvageable, then they can be given a wood hardener to strengthen the timber.
However, any structurally affected timbers should be removed and replaced.
Carry out any necessary repairs to the property to prevent future dampness, such as increasing the ventilation within the roof space.
If it was dry rot, how would you have advised the client?
If it was dry rot, I would have advised the client to:
* Find and remove the source of dampness that caused the dry rot.
* Cut away infected timber at least 500 mm beyond the last signs of fungal growth. Remove all visible spores and fruiting bodies.
* Replace the removed timber with pre-treated timber.
* Apply a fungicide or dry rot treatment fluid to the remaining wood.
* Increase ventilation in the affected area to promote drying.
* Use a damp-proof membrane to prevent dry rot from returning.
* Use a masonry dry rot treatment to sterilize masonry surfaces.
Are you aware of any recent techniques used for treatment of an active dry rot outbreak?
- Epoxy treatments - Filling in gaps within the damaged wooden structure with an epoxy treatment can kill the rot and strengthen the wood’s structure.
- Commercial antifreeze - Antifreeze can be used to kill the fungus and prevent further growth of dry rot.
When advising your client at The Crescent, why did you recommend the paving should be removed and reinstated 150mm beneath the existing DPC?
I provided this advice because external ground levels should be lower than the damp proof course to prevent rainwater from splashing over the DPC, control rising damp, and allow for evaporation at the base of the wall.
How do you test walls for damp?
I use a moisture meter, which can measure the moisture levels in walls, floors, and timbers.
There are two main types of moisture meters:
Pin-type: These meters use two probes to measure the electrical resistance between them. The more damp the material is, the higher the reading will be.
Pinless: These meters use electromagnetic signals to detect moisture without damaging the surface.
Thermal imaging cameras: These cameras translate heat into visible light to help identify damp areas.
Visual inspection: This is the most obvious tool, but it can be useful.
How did you know that the paving was bridging the damp proof course at The Crescent?
I took measurements both internally, within the front living room and externally from the window sill to the ground. This confirmed that the level of the path was above the internal floor level.
This would mean that any water that penetrates or is absorbed into the wall, at the external ground level, would be able to work its way into the inner face of the wall and cause damp within the living room.
How did you know that the timber frame to the timber clad balustrade was rotten at Sylvan Estate?
Following the removal of the cladding, the frame had cuboidal cracking and was crumbly to the touch. It was cracked and was begging to crumble apart.
Why did the absence of any membrane matter, when you uncovered this during the Walkway works at the Sylvan Estate?
A membrane would have prevented any of the moisture penetrating the concrete slab and causing damp issues within the flats below.
During the walkway works at the Sylvan Estate, how did you instruct the contractors to form a fully encapsulated waterproof detail between the balustrading and concrete slab?
As the concrete slab and detailing around the windows was vulnerable to water penetration, I informed the contractor that we needed a detail to encapsulate the exposed edge of the slab and the window head.
I discussed this with the roofing manufacturer who provided a detail that they were willing to guarantee.
What are the typical defects of a flat roof? What are the remedies?
Crazing
Surface crazing is caused where there is a lack of adequate protection from the
harmful effects of exposure to the sun or, in rare occasions, chemical attack. If this
is only in small, localised patches no treatment is necessary but should be regularly
rechecked. If more widespread the areas will have to be re roofed and specialist
protection introduced
Blistering
Blisters can be caused by water vapour pressure occurring below the roof covering.
The blister should be cut and then re-bonded to the underlay allowing any trapped
moisture to escape first. The source of the moisture should also be traced and
rectified.
What other sorts of cracks would you expect to see on a brick building and what might have caused them?
Subsidence — A movement down in the ground level. In clay soil, the growth of large trees which remove water from the ground can cause this. This can lead to vertical cracking if in the centre of the building or diagonal cracking if at the corner of the property. The cracks will be larger at the top and thinner at the bottom.
Heave — A movement upwards in the ground level. In clay soil the removal of a tree will lead to an increase in the moisture content of the soil which will cause the soil to swell. This leads to vertical cracking if in the centre of the building or diagonal cracking if at the corner of the property. The cracks will be larger at the bottom and thinner at the top.
Settlement — A movement down due to an increased load. Buildings will settle when first constructed or if there is a change in the load as the new load settles to the bearing capacity of the soil.
What is damp?
A building is only considered to be damp if the moisture becomes visible through discoloration and staining of finishes or causes mould growth, sulphate attack, frost damage or even drips and puddles.
How would you identify rising damp? What are the causes? How would you remedy it?
RISING DAMP - Inn high tide mark, peeling and blistering of wall finishes, musty smell, rotting of timber, hygroscopic salts. Use of Speedy carbide meter to measure moisture. The readings with moisture meter result in high surface readings, often with slight decline, finishing with a sudden cut-off
CAUSES — No damp proof course, DPC bridged by pointing, render, soil, paving, mortar droppings, affects both solid and suspended floors.
REMEDY — Remedy DPC problems, remove bridging of DPC, chemical injected DPC
- What type of soil is susceptible to heave and what are the possible causes?
Cohesive soils such as clay. Possible causes include removal of trees, change in water table, leaking drains or inadequate foundations that are built within the movement zones.
What are the common defects associated with flat roofs?
Common defects associated with flat roofs include blistering and splitting of covering, sagging (due to failure of decking between joists), ponding (due to insufficient falls), damages to flashings, inadequate solar protection.
What are the different stages of construction and what do each of them entail?
Project Inception
This includes the project conception, design, and planning. A feasibility study is often conducted to determine if the project is possible, and to identify any areas that need adjustment.
Pre-construction design.
This includes preparing for construction work, such as obtaining planning permission.
Procurement
This involves sending the project out to tender, to appoint a contractor.
Construction
This includes all aspects of building, such as foundation construction, superstructure construction, exterior work, and interior work.
Post-construction
This includes the project close-out and occupancy. It also includes a period of rectification, where any issues are repaired before final payments are made.
Why are building regulations important?
The Building Regulations are intended to protect people’s safety, health and welfare in and around buildings. The regulations are also designed to improve conservation of fuel and power, protect and enhance the environment and promote sustainable development.
At Maybank Road, what were the Building Regulation requirements for sound reduction between flats?
The walls and floors required a minimum performance of 43 db, which was achieved through a variety of different details such as resilient bars, acoustic hangers, acoustic insulation and acoustic plasterboard.
The separating floors had to achieve a maximum impact sound level of 64db. Again, this was achieved through floating floors and acoustic underlay.
What is a Planned Maintenance Programme?
Planned preventative maintenance (PPM) is a proactive programme that ensures buildings and operate efficiently and are protected from decay and dilapidation. If instructed to provide a PMP, I would inspect the property to provide a written report on the condition and also provide a capital expenditure plan, which is a recommended maintenance schedule, with budget costs for each element.
This help clients to plan for future maintenance and begin to make the necessary steps to ensure the funds are available when required.
What is a septic tank?
A septic tank is a buried, watertight container that holds wastewater and partially treats it.
A septic tank has two main elements.
1. The underground tank.
2. A drainage field.
What are the maintenance issues with a septic tank?
Septic tanks require regular maintenance in order to function properly. The most regular form of maintenance is the need to ensure the levels of bacteria within the system are topped up.
They also require cleaning and emptying to remove solid waste that accumulates are the bottom. However this is only required every 3-5 years.
Why do you specify a lime mix pointing to historic buildings and when did you last do this?
Building materials used to construct historic buildings are generally considered to be porous and have the ability to let water and air pass through, hence why historic buildings are often referred to as being breathable. Lime is a traditional building material and is both breathable and flexible, which helps prevent moisture damage and allows the small movements within the masonry without cracking.
If I was to specify a cement mortar, which is not porous, flexible or breathable, this would prevent the building performing how it was originally intended to, leading to damp and mould growth as well as cracking.
When is a lime mix pointing or render not suitable?
Lime mortar is not used in all mortar because it has some disadvantages compared to cement mortar, including:
Strength - Lime mortar is not as strong as cement mortar, so it’s not suitable for all types of building applications.
Ease of use - Cement mortar is easier to use than lime mortar, as it sets quickly and is less labour intensive.
Drying time - Lime mortar takes longer to dry than cement mortar, making it more time-consuming to install.
What are the benefits of using a lime based mortar/render over a cement alternative?
One of the key benefits of lime render is its breathability. Lime allows moisture to evaporate, preventing trapped moisture from causing damage to the underlying structure. In contrast, cement render tends to be less breathable, which can lead to moisture issues and potential structural damage over time.
It is also more flexible and durable, so less prone to cracking when the building or structure moves.
Why did you incorporate a lead capping detail to straddle two separate dormers?
The proposed works included constructing a dormer extension up to the line of junction. This meant that the existing vertical hanging tiles to the adjoining owners extension were to be removed, to allow the construction of the dormer. As there would be a 25mm vertical gap between the two dormer extensions, I believe that once the extension has been constructed, tiles and the flat roof detail had been completed, a lead flashing should also be dressed over the gap between the two extensions at roof level to prevent any water penetration into the gap, or build-up of debris within the gap. Which would be almost impossible to clean or maintain.
Why did you need to comply with Part L, when carrying out the roofing works to Bouverie Lodge?
If you are refurbishing more than 50% of the roof, you are required to comply with Part L, which requires a U-Value to roofs of 0.18w/m2k or lower.
What did you ultimately advise the client at Bouverie Lodge regarding the roofing scheme?
The due a number of different factors, I advised the client to proceed with a mixted scheme, formed with both 130mm flat board and 60mm vacuum packed insulation. Although he vacuum packed insulation was very expensive, this option was more cost effective than removing all of the doors and raising the thresholds.
The roofing manufacturer also confirmed that they would be able to design a scheme to provide a 30 year guarantee.
Is there such thing as rising damp?
Yes. Rising damp is when moisture from the ground travels up through the walls via capillary action.
What are the common issues resulting in dampness to properties internally?
Penetrating damp, rising damp and condensation.
Can you tell me about the rectification period under the JCT MW Contract?
Unless otherwise agreed, the rectification period is 3 months, from the date of practical completion.
The contractor is responsible to put right any defects in the work which appear during the rectification period, before he is entitled to be paid the final balance of the contract price.
The CA is required to notify the contractor of any such defects not later than 14 days after the expiry of the rectification period.
