Client: Domestic
Our client, a homeowner in Pudsey, tasked Timberwise with carrying out a pre-purchase survey for problems associated with atmospheric moisture/condensation, dampness, woodworm, and wet rot fungal decay. This property was an end terraced house of solid stone construction, and was both unoccupied and part furnished at the time of our inspection. The property had finished completion in 1900.
We noted a number of remedial issues during the survey, including active wet rot fungal attack, elevated relative humidity/condensation, widespread black spot mould, chimney breast dampness, and external building maintenance defects. The weather conditions were sunny at the time of the survey.
Challenges
Our internal inspection was restricted due to the property’s fitted units, tiled walls, furniture, stored items, fitted floor coverings, insulation, and solid floors. The property was unoccupied during the inspection, meaning we had no challenges when being mindful of tenants.
The external inspection was restricted to a ground-level visual assessment only.
The property had inherently restricted natural airflow due to the back-to-back layout of the property. High external ground levels were also breaching the damp-proof course along the front and right elevations. The chimney’s defects were also a challenge when it came to remediation, as it was retaining moisture and causing noticeable salt migration.
We noted that the black spot mould on the first floor had been painted over with white paint rather than being properly resolved. There was also inadequate existing passive ventilation which prevented the property from being compliant with Part F Building Regulations 2010.
Observations
The external assessment of the property presented us with a number of immediate problems that would need quick attention. There were a number of missing and slipped roof tiles to the front elevation, which was causing a major risk of water penetration. There were also defective flashings to the right chimney stack and parapet wall.
Water straining to the front elevation’s guttering indicated active leaks that were likely to cause damp inside the property. We also noted isolated areas of defective mortar pointing on the front elevation, the right elevation, and chimney stacks.
For the lower part of the property, we noted that there were high external ground levels relative to internal floor levels and damp proof course on both the front and right elevations. There was inadequate sub-floor ventilation along both the front and right elevations, twinned with defect front elevation cellar bricks that did not connect through to the cellar. There was a chemical injection damp proof course present at the property, but no apparent damp proof course on the right elevation.
Inside the property, our surveyor found a large condensation problem that permeated most of the building. High relative humidity readings were taken in key areas, including 80-85% in the basement and 70%–75% in the bathroom. High surface moisture profiles and readings were found across tested internal walls. Black spot mould was present throughout the property on both the ground and first floor levels.
There was inadequate ventilation and mechanical extraction units in both the kitchen and bathroom, which was leading to the problem of condensation and black mould. There was also an absence of passive ventilation such as trickle and wall vents or door undercuts.
We found excessive dampness accumulating on the ground and first floor chimney breasts, which had resulted from historic fossil fuel burning and hygroscopic ammonium salt migration. The chimney void was also sealed and unvented, which was also trapping moisture inside the property.
There was an active wet rot (Phellinus contiguous) attack found on the ground floor, in the front right room. This was likely caused by the property’s condensation problem, elevated external ground levels, and poor sub-floor ventilation.
We found no evidence of an active woodworm infestation in any part of the building.
Solutions
Prior to our technicians’ arrival, the customer will be required to remove all floor coverings, radiators, pipework, furniture, fixtures, fittings, and stored items in order for the team to have full access to the affected areas.
For the timber treatments in the ground floor’s front right room, we will remove and replace the affected floor joists in the ground floor’s front right room with a new pre-treated timber hoist. We will also apply fungicidal treatment to all cut joist ends. The joist ends will be isolated from the masonry with the use of a damp-proof membrane. All timber waste will be completely removed and disposed of off-site.
To control the condensation problem and introduce more ventilation into the property, we will supply and install a continuously running, intelligent 12V DC EnviraTek humidity-tracking extraction fans with day loggers and energy-saving cowls on kitchen and bathroom external walls. We will execute the core drilling, electrical work, and product commissioning in full accordance with NICEIC Part F standards.
We also gave some recommendations to the client to be sourced by other contractors that were outside our remit but would be hugely beneficial in improving the property. We advised surface cleaning and biocidal sterilisation of all black mould prior to any redecoration and improving cellar ventilation through the introduction of passive air bricks or a ventilation unit.
We also strongly advised the client to introduce internal vents at the ground and first floor levels for the chimney breasts to help with air circulation. What also may need to be done is isolating the chimney plasterwork using a membrane system or salt-inhibiting renovating plaster if the problems continue to persist.
Recommendations also included lowering the external ground levels to below the internal floor level, or applying a waterproofing tanking coat to the sub-ground masonry. The client was also encouraged to implement a regular heating regime with passive ventilation additions, such as window trickle vents and door undercuts.
Results
We provided the client with a clear plan to completely eradicate the active wet rot attack and remediate the decay caused by structurally replacing the floor joists and using a fungicidal spray to kill the outbreak and remove any active fungal spores and surface black spot mould.
We will optimise indoor air quality, air changes, and humidity control across high-moisture zones such as the bathrooms and kitchen. Our plan would provide the client with long-term prevention of condensation damage, lateral damp ingress, salt migration, and timber case. We will also implement EnviraTek condensation control extraction units, which comes with a 5 year full parts, labour, and call-out warranty.
Do You Want Help with a Condensation Solution?
Our dedicated and experienced team in Bradford are ready to talk to you about your options for property preservation. Don’t hesitate to call us on 01274 891675, or you can request a survey online.
