PIV damp proofing risks mould

Background

In a ground floor flat of a Victorian terraced house, extensive efforts have been made to address persistent damp issues without resolution. The property, previously treated for rising damp, despite no evidence of groundwater or significant external concerns, now shows signs of mould and condensation, primarily on colder surfaces with restricted airflow. Internal factors such as a Positive Input Ventilation (PIV) unit, used for drying clothes, contribute to excess vapour. Additionally, the presence of an unoccupied neighbouring flat leads to colder walls. Ventilation assessments indicate a need for improvement, especially in the bathroom. The primary cause of damp is excess vapour from indoor activities, exacerbated by inadequate ventilation. Recommendations focus on reducing internal dew points through targeted ventilation and dehumidification, advising the use of dehumidifiers near drying clothes and in sleeping areas, and suggesting relocation of furniture away from cold walls to mitigate condensation and mould risks.

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Data loggers – awaiting tenant data due year end

This is an example, two data loggers (hygrometer continually measuring humidity and temperature) were used. One was left by the mouldy bedroom windowsill, the other above the door inside the nearest wet room, the internal bathroom.

Example above focused on dew point. Dew points are critical to reducing through ventilation and dehumidification. A well ventilated property will have dew points at or near the external temperature. External temperature forecasts can be found from weather forecasts or in London from, https://MouldPoint.co.uk.

In conclusion, from the data loggers

At the time of the “PIV damp proofing risks mould” survey, the surface relative humidity is above 85%RH behind the living room sofa, when mould growth is at risk at the time of the survey.

Evidence & Illustrations

The following is an explanation for the root cause of damp and mould in this property, followed by solutions.

The tenants primary concern was mould, for example behind this sofa. Mould growth occurs where relative humidity exceeds 85%RH for more than six hours. Excessive humidity is usually due to insufficient ventilation, poor air circulation, and cold surfaces. Relative humidity measures the amount of vapour in the air relative to the air’s capacity to hold vapour. It is influenced by vapour pressure and temperature. As temperature rises, the air can hold more vapour. Conversely, as temperature drops, the air’s capacity to hold vapour decreases until it reaches the dew point at 100%RH, resulting in the formation of dew or condensation.

The data logger measures 15.0°C and 83%RH on the hygrometer data logger.

The surface behind the sofa is naturally colder at 14.5°C.

If you look at my mould point calculator, refer to previous video, you will see that the surface relative humidity at the time of the survey was 85.2%RH, providing ideal conditions for mouldgrowth.

The thermal lens, where blue is about 5°C colder than yellow, highlights areas of heat loss. Much of the wall was below the dew point of 12.1°C when condensation forms.

Condensation dribble marks can be seen above a radiator. I understand the neighbour’s property has been left unheated during probate. It will therefore act as an outside wall, but with typically poorer insulation. Radiators act to slightly remove heat when not in use, as water is marginally circulating.

The sofa is trapping air. I discuss this more in other videos, but in essence, the dew point, which is an exact proxy of vapour quantity, will be the same across the whole property, but the sofa is effectively insulating the wall from warm air currents.

It is particularly damp and mouldy in the corner. Corners are exposed to additional surface area. Albeit a terrace, the cold neighbour, and there cold attached wall, will increase the heat loss in the corner. Condensation appears to be forming on window sill, pouring down onto the wall.

There is a PIV system, I know the sale pitch and have friends that manufacture these units who swear by them. However, they do feature in roughly 5% of my damp surveys, suggesting either the installation, use or basic assumptions are wrong. Installation: guidelines ay there needs to be adequate bathroom and kitchen extraction, which as you will see there was not. Use: placing clothes next to the PIV unit shows a misunderstanding about the function. I don’t blame the tenants. It takes someone with my experience to see the mould risk.Basic assumptions: blowing external air in will dilute internal air. While this is correct; a) Vapour is liable to escape through the nearest gap, for example a trickle vent, this often creates a shortcut leading to a marginal dilution effect. It is much better to remove vapour at source, such as with a bathroom extractor. So, a continuous bathroom extractor will be a better solution as well as much cheaper, I have installed one in my own house and rental flat, bought at auction with extensive mould. b) The air blown in will contain external vapour. If it is raining outside the external dew point (vapour quantity) could easily be above the internal dew point, thereby being counterproductive. c) User may be lulled into a false sense of improvement. d) Typically occupiers don’t like the cold air coming in. Some PIV units have a heating element, but this is expensive to run and if there is a shortcut, heated air will be pushed out, increasing CO2 emissions, limiting the benefit.The one positive is, hay fever suffers will benefit from the filters. But to be effective, filters need annual maintenance, which is expensive.

Clothes are dried by a heating next to the PIV, this appears to be reducing the dry time, but pushing vapour onto cold walls, increasing the mould and condensation risk. It is much better to use a dehumidifier for the property, occupier health, vapour reduction, energy consumption and CO2 emissions, as all energy consumed by dehumidifier results are heat, with a 50% bonus from enthalpy, like an air-source heat pump.

The wall was damp, as indicated by a Protimeter radio frequency damp meter. The meter measured 999REL, signifying saturated pores deep within the wall. Readings below 300REL are dry. These meters assess the extent of damp and are used to trace it to the source.

On the external wall immediately behind the sofa, there is a plastic storage box with damp wall. Rainwater tends to bounce off objected near to an external dampening brickwork, that then doesn’t dry as a fast because of the reduced airflow. Rain is not penetrating through, but a damp brick is a poor insulator, increasing the risk of heat loss and therefore condensation and mould.

Condensation is forming on windows, running to the wall below.

This was particularly visible on the front window.

Although the stain is a classic sign of penetrating damp, in this case the discolouration is coming from condensation pouring over the timber window frame.

The line of drill holes (which some refer to as “bullet holes”), tells me that the flat has previously undergone damp proofing treatment, despite the low risk of risk damp. Rising damp comes from groundwater which is pump out in most cities, such as London about 30M below ground, to reduce the risk of flooding in underground railways and parking.The downside of rising damp proofing treatment, is builders tend to replace standard internal plaster, that absorbs and evaporates off vapour, with impermeable slurry, that does not. Breathing is often used as an analogy for absorption and release of vapour, although the damp proofing industry ridicules this analogy. The point being that replacing half the wall with impermeable slurry, which can absorb as much as plastic or glass, reduces the natural buffering of vapour. This increases the risk of mouldand condensation. If you look at other reports in the new year, you will see examples of calcium sulphate salt crystals forming on the interface between the slurry and original plaster.

There is a green stain to the front. It looks fresh. The tenants told me that the rainwater goods had been fixed. The rainwater goods (guttering and down-pipe) looked to be in a reasonable state. You or the tenants should film the rainwater goods during a rainwater to ensure water is not overflowing. If it is then instruct a roofer or gutter expert to adjust the gutters accordingly. Also note that ideally the front pipe should be extended by 2M or so from the front.

Passive vents, i.e. one that don’t have an electric fan often have condensation and mould around them as is the case here. The issue is there is only airflow in when there is wind outside. In this case the cupboard is obstructing the airflow, so there is heat loss, without much ventilation.

The thermal image highlights the heat loss.

Mould is growing at the cold base of the bedroom wall. Mould growth is inhibited by nitrates found in groundwater. The presence of mould at the bottom of a wall rules out rising damp as the root cause and points towards condensation from unvented excess vapour.

The thermal image highlight the heat loss in the section of wall between the front of the building and front door. This section of wall is external, compared to the other side which backs onto the shared corridor.

This thermal image highlights heat loss in the damp front bay corner. Corners have more external surface area, increasing the heat loss. The base of a wall, close to the ground, will tend to be colder than higher up. Dampness is drawn down by gravity. Once damp, plaster and brick will lose insulation, increasing heat loss. All of these factors make the front bay particularly vulnerable to mould and condensation. Damp at the base of a wall is often cited as an example of rising damp. However, all source of dampness, including penetrating damp, leaks and condensation will tends towards the base of a wall. The profile of damp in this case is classic condensation. The primary solution will through ventilation and dehumidification, but vapour active insulation could be valuable.

The bathroom extractor fan is running slowly at 6.1 litres / second, the overrun was short, left on the factory default of 1 minute. I cleaned the fan out and increased the speed to just over 10L/S and increased the overrun to 30 minutes. The tenants had been told to keep the door open. The problem with this is vapour from the bathroom will diffuse around the property, see details in videos from other properties.

The PIV unit has ducting which creates a cold spot in the bathroom, increasing the risk of condensation. I am not necessarily one for advising landlords remove PIV units, especially if they have tenants that suffer from hay fever (current or future). But if it were my flat, I probably would probably remove the PIV unit, or if not, at least insulate around the final section of ducting and adjoining wall, say 300 – 600mm. Then give the tenants the option to run it or not, but with a strict policy of using kitchen and bathroom extractors, dehumidifier, while monitoring internal dew points, possibly remotely.

I like ProBreeze dehumidifiers, however, I suspect this one is the 12L/day version. Ideally it should be 20L/day. Note it was not on. I think the tenants said that was to give more accurate background data. In addition to other recommendations, I would have the dehumidifier run 24/7 until the walls are dry and mould free and then whenever drying clothes internally or internal dew points are above the external temperature.

The kitchen extractor fan worked well. However, the tenants told me that that ducted it was connected to the outside. This suggests that they didn’t think it worked and therefore did not use it. Post Covid working from home has dramatically increased the amount of vapour released by occupiers during the day from an extra 1/2 L per person and typically more cooking lunches. Kitchen extractor fans are noisy and therefore rarely used by tenants. I would require its use and an explain to tenants why removing vapour from cooking is important.

There is mould growing above the trickle vents. Trickle vents are passive vents, there to provide essential background ventilation. While the theory behind trickle vents is sound. In practice they often increase the risk of mould as seen here. It could be poor installation, such as only drilling out a few holes, blockage from dust, or simply insufficient airflow relative to the heat loss, increasing surface humidity, rather than reducing it.

There is rust on plasterer’s beading around a fireplace. Rust results from condensation.

There is condensation of a metal door lock, another signs of excessive vapour levels.

Single glazed windows act as dehumidifiers removing water from the air. It is a good idea to remove water with the condensation vacuum cleaner.

As you will hear from the video, I spent time talking to the tenants about how to reduce the internal dew points, by targeted ventilation and dehumidification. I would say you tenants are willing to do the right thing, they just were unaware of how vapour is generated, how to remove it and keep the place mould and condensation free – as I always say it take teamwork between tenants and landlord.

To keep the property dry
Lower internal dewpoint
Monitor relative humidity and temperature against the wall or ceiling to observe the effects of improvements, such as ORIA Wireless Thermometer Hygrometer (20m (2 Packs)) – already in place. In addition monitor improvements on the damp wall a pencil line and damp meter such as dr.wood moisture meter, logging improvements each month. Monitor relative humidity and temperature against the wall or ceiling to observe the effects of improvements, such as ORIA Wireless Thermometer Hygrometer (20m (2 Packs)) – already in place. In addition monitor improvements on the damp wall with a pencil line and damp meter such as dr.wood moisture meter, logging improvements each month. Use Mouldpoint.co.uk as a daily reference for dew points and temperatures. As a landlord consider monitoring with a WIFI connected datalogger, such a SwitchBot SwitchBot Room Thermometer Hygrometer plus Mini Smart Remote Control (hub) – as I do myself for remote monitoring.	£30
Ask tenants to remove vapour from bathroom
Ask tenants to keep the bathroom door closed with the fan running or window open until the humidity from the shower has subsided – typically at least 30 mins after the last shower. Consider adding a spring to the bathroom door as an extra reminder.
Ask tenants to remove vapour from clothes drying
I would provide tenants with a means of drying clothes internally, which could be a powerful dehumidifier or tumble dryer (like a heat pump). Alternatively ask them to dry in an vented room with the door closed (possibly a bathroom with the extractor running or window open). Ask tenants to never to dry clothes in an unventilated room. Consider offering to pay for the cost of running a dehumidifier or heat pump dryer, in the region of £1 per day, plus it is energy efficient as all energy is converted to heat plus a 50% bonus.
Ask tenants to remove vapour from cooking
Cook with tops on pots and pans to reduce the production of vapour from cooking by 80%.
Maintain airflow close to cold walls
TIP: Keep objects away from walls where condensation or mould has built up. Move sofas from walls and insulate behind cupboards on cold external surface for example, with floor insulation from B&Q or Wallrock Thermal Liner (ensure to use Wallrock Thermal Liner Adhesive).
Remove mould
Consider sanding down mould where dry, and removing it with either bleach or anti-mould foam. I personally use HG Mould Remover Foam Spray, but imagine there is no major difference between brands.	£100
Use fan to expedite drying
Direct a fan onto the damp patch to speed up the drying process.
Remedial actions – estimate of costs	£130

This estimate is based on approximate time, costs and competence to complete repairs. It is not a quote for work. We are independent. A general builder can complete most work. trustedtraders.which.co.uk is good sources of general builders. Once the recommended remedial actions are completed and the walls allowed to dry, dampness will not have a material impact on the value of the property. It is the client’s responsibility to check that a contractor has sufficient insurance and competence to undertake any work that we recommend.

Actions if all else fails
Consider installing a continuous flow bathroom extractor fan
Continuous bathroom extractor fan run with multiple settings, when light are switched on, to background ventilation. You will see from other reports, that it is imperative to set the fan up correctly, typically manufacturers concern themselves about noise levels, so set fans up to the lowest speed and overrun, but this is often inadequate. Make sure to set the flow rate after setup, see another report being written, title ’50k loss after Kenwood quote’	£400
Consider replacing or adding to dehumidifier
Maintain relative humidity, especially at night when it’s cold outside, with a dehumidifier such as Pro Breeze 30L Smart Dehumidifier £239.99, PureMate 20L/Day Portable & Compact Dehumidifier with 6.5 Litre (£179.99 Refrigerant), Duux Bora Smart Dehumidifier (DXDH02UK £300 Refrigerant) or Meaco DD8L Zambezi (£260 Desiccant – best for colder environments) – Which! Best buys. There are plenty of alternatives available. I choose a dehumidifier based on daily and tank capacity, low noise, whether it has a pipe out, and ease of programmable functions over other considerations such as weight and aesthetics. The technology is old and easy to manufacture. So if these brands are not available, you are sure to find another alternative. Evaluate based on daily capacity (20L minimum) and whether it has a continuous pipe out (use this to drip into a sink when away in winter).	£240
Consider targeted insulation.
Consider installing vapour permeable thermal insulating plasterboard or thermal lining paper such as Woodfibre, such as wallrock thermal liner to cold surfaces. It is a bit trickier insulating Infront of slurry as this can cause condensation within the wall. You should refer to the damp proofer – consider removing the damp proofing, external wall insulation. Wallrock thermal liner should work, but it is not a replacement for dropping dew points to the external temperature.	£1,000
Optimal actions – estimate of costs	£1,640

I conclude that excess vapour from bathroom, internal clothes drying, insufficient kitchen extraction, cold neighbour side, increased home occupancy.

PIV unit exacerbates vapour issues, better ventilation and dehumidifier use recommended

Extended bathroom extractor fan overrun to 30 minutes. By taking a root cause approach, rather than a focus on blocking the symptoms of damp the savings are likely to be around £5,000. This contrasts with typical damp proofing contractor recommendations such as chemical treatment for rising damp and untargeted ventilation, such as PIV systems.

Flood risk: No risk See Flood Risk (note most flood risk is not from groundwater).
Sub-soil rocks: Rocks with essentially no groundwater See British Geological Survey.
Therefore risk of Rising Damp: remote possibility, see explanation by Dr Robyn Pender of Historic England.

I confirm that I inspected the property on 231211SH1000. I conclude that excess vapour from bathroom, internal clothes drying, insufficient kitchen extraction, cold neighbour side, increased home occupancy. All buildings can be exposed to unvented vapour and external dampness to some degree. You will mitigate the risk of damp if you follow all our recommendations. This report is intended to be read in full including supplementary links in this report. Observations and opinions must not be taken in isolation. Given the right weather conditions almost any house can be affected by rain. Like any building, you need to be aware of the risks of damp arising in the future and should plan a programme of monitoring, prevention and maintenance accordingly. Damp Surveys Ltd reports are designed to provide you with an informed, independent expert opinion as to the cause of dampness in the property, together with any recommendations for further investigation or remedial work. We do not warrant any findings in this report unless we enter into a separate warranty agreement with you.

The survey was conducted during daylight hours. Damp will be more noticeable at night and when the weather is colder and more humid. Gutters are more likely to fail when full of leaves and during periods of prolonged rain and adverse wind. We make best endeavours but cannot guarantee being able to identify all forms of damp, rot and insect infestation affecting the property.

We carried out a careful and thorough inspection of as much of the property as was accessible. However, when a full inspection is not possible, we make a professional judgement regarding the likelihood of a defect being present. In certain circumstances, this may lead to a recommendation for further action to open up an area for additional investigation. We were unable to inspect the entire roof, all the guttering, and some of the drains. Similarly, inspection of woodwork or other parts of the structure that were covered, unexposed, poorly lit or inaccessible such as in the loft, cellar, or sub-floor void was not possible, and therefore we are unable to assert that such parts of the property are free from defect. There were no obvious signs of damp resulting from these limitations

Negligence claims must be made within 90 days of the damp survey site visit. Clients must make best endeavours to monitor humidity and temperature on a damp wall and the closest source of humidity, by purchasing and placing two data loggers for example the Smart Hygrometer measuring humidity on the wall and nearest source of vapour, before and after following our recommendations. These data loggers have sufficient memory capacity to store 90 days of data.

This report is for the sole use of the client (named on the invoice, but omitted here for anonymity) for whom the survey was undertaken and can only be relied upon for 90 days from the survey date. Unless expressly stated otherwise in this report, nothing in this report confers or is intended to confer any rights on any third party pursuant to the Contracts (Rights of Third Parties) Act 1999.

Simon Hichens

Site visit 231211SH1000

Simon Hichens BSc Chemistry RICS Qualified Expert Witness (Chartered Surveyors)
PCA Certificated Surveyor of Dampness & Timber in Buildings (Property Care Association)
Damp Surveys Ltd, 119 Longton Ave London SE26 6RF Reg. 10977488 (England & Wales)
Founder of damp.aï & Member of the Society for the Protection of Ancient Buildings (SPAB)

Our damp surveys are designed to provide a holistic diagnosis that identifies and deals with causes rather than a focus on symptoms. Symptoms will disappear over time, once damp is stopped at source. We look for risks of dampness, but unless moisture is present, we can’t guarantee to identify all risks of future moisture. Our reports:

identify root cause(s) of major unwanted dampness within the property,
identify major symptoms of unwanted dampness,
identify major structural damage caused by dampness,
recommend actions and estimated costs to stop damp at source and mitigate its effects,
recognise that treating damp is often a staged approach, treating obvious causes first.

Note neither condensation nor rising damp are causes. They are symptoms.

Understanding damp

For survey purposes, damp is defined as unwanted water. Water brings life. We need it. Unfortunately, fungus and insects also thrive in water. While a damp wall can cause decorative spoiling, it is not moisture, but the life it brings that causes the greatest concern in the home environment. FACT: vapour causes 85% of residential damp problems.

Independence and Methodology

Our only income is through damp survey fees. We are independent of contractors and never profit from remedial work. We do not receive or pay any fees or other inducements. Our motivation is peace of mind and practical, durable solutions. We use an array of equipment to identify the root cause of damp within walls. Our damp surveys follow guidance from RICS, Historic England and PCA joint position statement and support RICS’s highest standard, level 3 “Home Survey Standard” (HSS).

During the survey we assess likelihood of rising damp*, mainswater leak, penetrating damp, condensation, timber rot and woodworm. We profile the damp patches and consider the likely sources of dampness and test ventilation against building regulations requirements. We consider changes to the property and factors just before the first sighting of damp.

Rising damp concern: Rising damp previously treated, but current issues likely due to condensation and mould, not rising damp.
Damp treatment: Despite the low risk of rising damp, there has been an attempt at chemical treatment against rising damp. Rising damp treatment is normally a sign of insufficient ventilation. The walls have been drilled into by about 200mm and injected with damp proofing chemicals. In theory the chemicals are absorbed into the brick pores reducing the bricks ability to absorb moisture. Walls are replaced with damp proofers slurry. This can cause problems with absorption imbalance, resulting in increased condensation on other walls or vapour becoming absorbed and trapped behind the slurry. There was evidence of surface condensation in areas probably not treated with replacement plaster but no evidence of trapped vapour. The solution is through ventilation and humidity control.
Weather: Dry overcast
Property: Ground floor flat in a Victorian terraced house
Background: Extensive unresolved damp issues despite significant time and money spent
Changes: Conversion to flats, rear extension, damp proofing, PIV unit installation, increased home occupancy post-Covid
Occupancy: Couple
Mould & notes: Mould present on cold surfaces with restricted airflow, signs of condensation
Primary damp concern: Mould and condensation
Other damp concerns: n/a
Compounding: PIV unit used for drying clothes, contributing to humidity
Airbricks: No concerns
Sub-floor humidity: No concerns
Tenure: ground floor flat
Attachment: Terraced with back addition, neighbouring to an unoccupied, cold flat
Build: Victorian
Walls: 9-inch thickness
Exterior comment: Minor greenery on front left side, I understand that guttering and downpipe recently replaced
Penetrating damp assessment: Possible past rainwater ingress, no current penetrating damp
Drains: No specific concerns
Leak signs: No specific concerns
Leak assessment: No leak risks identified
Floor: Good condition suspended timber floor
Loft: No loft
Timber assessment: No timber concerns
Last dry: Issues ongoing since Covid, possibly earlier
Ventilation assessment: Bathroom extractor fan slow, overrun extended to 30 minutes, replacement recommended

W.H.O. indoor air quality guidelines

“Management of moisture requires proper control of temperature and ventilation to avoid excess humidity, condensation on surfaces and excess moisture in materials. Ventilation should be distributed effectively throughout spaces, and stagnant air zones should be avoided.”

FACT: Houses contain 30 – 40 litres of water as vapour typically. Each day, each occupant adds on average about 1.5 litres as follows:

Each shower results in 1/2L condensing (each additional shower in a series won’t add as much as the first, so long as the door is kept closed)
Vapour from drying clothes releases about ½ litre per day if dried indoors
Respiration releases about ¾ litre per day (of which ¼ l at night)
Cooking produces about ¼ litre per day per person
Unvented vapour can cause condensation, mould and allergenic dust mites. The simple rule for keeping your property dry and mould free is;
Vent out as much vapour as produced, each and every day!
Central heating and double-glazing reduce background ventilation. To overcome this you should use mechanical extractors. Where properties are rented, consider using monitoring devices (such as a Govee WIFI hygrometer) and if necessary, install continuous flow extractors, but beware there can be a thermal cost caused by continuous heat lost.

FACT: dehumidifiers are a win-win as all energy is released as heat with a 50% bonus through enthalpy, but they need to be targeted to the source of the vapour or location of dampness and mould, should be insufficient, typically 20 L/ day theoretical capacity with 6 Litre container and decanted daily or drained into a sink or similar.

FACTS about Condensation and Mould

FACT: warm air holds more water vapour than cold air. The warmer it is, the more air’s capacity to hold water vapour. Conversely the colder it is, the less capacity, until air cannot hold any more vapour. We call that the dew point or 100%RH. As soon air reaches capacity, condensation will form on the coldest surfaces.
FACT: Mould and dust mites
FACT: Mould only grows when air is humid for long periods. In the occupied home environment, it is 6 hours over 85% RH. For properties that are unoccupied for long periods, it is 75% RH for many days of consistent and high humidity. Avoid allowing the surface relative humidity of cold walls to exceed 85% RH by ventilating, dehumidifying, insulating, and ensuring airflow, particularly in cold corners, base of walls and ceilings, eaves, and cold window and door reveals.
FACT: Dust mites are microscopic insects that can cause allergies. They grow in similar conditions to mould. So ventilate more to avoid allergies.
FACT: Health concerns: There are no health and safety issues from damp noted. It is in the occupier’s interests to keep a property properly ventilated or dehumidified and temperatures above the dew and mould points throughout the property, thereby reducing the health risk associated with dust mites, bacteria, protozoans, as well as decorative spoiling caused by mould.

TIPS To Stay Condensation and Mould Free

TIP: Reduce the production of vapour at source:
TIP: Keep bathroom extractor fans running, or window open for at least 30 minutes.
TIP: Keep bathroom doors closed at all times, and bathroom windows open safely.
TIP: When filling the bath, run the cold water first then add the hot.
TIP: Dry clothes outside, in a dryer, in a closed room with a dehumidifier or window open, never on radiators or heated rail without a door closed and a means of removing the vapour.
TIP: Cook with tops on pots and pans, avoiding excessive boiling.
TIP: Keep the kitchen door closed and extractor fan on where possible.
TIP:Mechanical vents are best, but if you only have passive vents, such as a whole in the wall or chimney, then vents open with space for air to move, insulate where possible.
TIP: Keep trickle vents open or alternatively, open windows on safety locks.
TIP: Stop mould forming:
* Maintain external wall temperatures above 12°C, with low background heating.
* Declutter leaving space for warm air to circulate around cold surfaces.
* Where possible, avoid placing wardrobes and furniture against external walls.
* Avoid overfilling wardrobes and cupboards as it restricts air circulation.
* Use dehumidifiers or small wardrobe dehumidifying bags and replace regularly.
* Wipe mould and condensation off walls and clothes as soon as it appears.
TIP: Monitor relative humidity
* We recommend monitoring temperature and relative humidity with a data logger to see what is happening.

Help It takes teamwork to solve damp and mould issues in properties. It isn’t easy or obvious. We can help with damp.ai. Time permitting the plan is to run online workshops for solving damp issues, within the community.

Background

Open Print or Save Refresh

Video evidence, tips & tricks

Data Evidence Explanations

Data loggers – awaiting tenant data due year end

In conclusion, from the data loggers

Evidence & Illustrations

Remedial actions

Recommended remedial actions

To keep the property dry

Optimal remedial actions

Actions if all else fails

Conclusions & reasoning

Conclusion summary for main concern

Reasoning

Root cause fix should save: £5,000

Risk of rising damp: remote possibility

Survey report & limitations

Site visit 231211SH1000

Damp & Survey methodology

Property & circumstances

W.H.O. indoor air quality guidelines

FACTS about Condensation and Mould

TIPS To Stay Condensation and Mould Free

JPS

Joint Position Statement

RICS, PCA, HISTORIC ENGLAND JPS REPORT

1 A summary of the surveyor’s observations, including an Assessment of Significance.

2 The importance of regular building maintenance and how a lack of even basic maintenance can lead to problems arising. This is especially important and relevant to roofs, gutters, hidden gutters, rainwater disposal and changes in external ground levels.

3 An impartial diagnosis of the damp problem, which should be clearly explained and laid out systematically to communicate the relevant risks to the reader.

4 Where recommendations for the repair and recovery of moisture-affected structures are stated, the solutions should be clearly explained and prioritised as appropriate.

5 The client should be provided with alternative options for which each recommendation should include advantages and disadvantages and the relevant cost and time implications.

6 Where monitoring and staged interventions are appropriate or beneficial, the client should be informed of the reasons for these options, together with the likely cost and time implications of such recovery strategies.

7 Where appropriate, clearly state whether the building concerned represents a financial risk to the buyer or lender and why.

8 Any conflicts of interest should be clearly stated.

Exemplar

AI & related examples

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