Client: Private School in Liverpool
Timberwise were called in to inspect a private education facility in Liverpool, to determine the presence and extent of problems associated with wood-rotting fungi in the roof areas of the property. At the time of the survey, the building was undergoing construction and renovation works and was therefore unoccupied.
This survey presented a challenge to our surveyors as it was under construction at the time of our visit, meaning that much of the property was relatively inaccessible and most of the outside was covered in scaffolding.
Observations
Most of the structure was covered by building scaffolds which made spotting defects on the external walls of the building difficult, even for our eagle-eyed surveyors. It was reported that the site was having issues with the roof leaking in multiple areas. Internal inspection revealed there had indeed been a few issues with the roof, allowing moisture to enter. This has caused staining and dampness to the underside of some of the timbers.
The defects noted had been allowing moisture to be transmitted into the building fabric. Not only would this be likely to spoil and damage internal finishes and decorations, but it would also put timbers within the building at serious risk from fungal decay (for example dry rot, or wet rot).
Upon our inspection, a large section of the roof was exposed due to the ongoing repairs. At the time of those repairs, decay was highlighted as an issue to some of the roofing timbers around the boxed lined gutters. Roof F7 – F5 revealed dry rot to the full section of the rear elevation timbers, the decay had broken down all of the timbers in this section, causing damage to the:
- Main support beam
- Rafters
- Wall plates
- Boxed guttering and framework
- Sarking board
- Internal wall and ceiling plaster
- Window lintels
- Window frames
Cause of the Problems
The cause was determined to be due to defective rainwater goods and roof coverings, allowing water ingress into the fabric of the property. In heavily affected areas, the walls may be full of dry rot strands, hence the usual requirement of plaster removal and wall sterilisation.
Recommendations
After surveying the property and assessing the damage from dry rot and dampness, our technicians recommended several works for repairing and reinforcing the building against further water ingress.
The main support beam was decayed in various areas, due to this the whole section would need to be removed and a new section fitted into place. Removal of the decayed ceiling timbers would also be necessary. The existing roofing rafters would need to be propped up, spanning the weight using boards and props from inside and below the work areas. The roof sarking boards would need to be removed so technicians would have access to the work areas. From this work area, rafters, large support beams, wall plates and boxed guttering and framework would also need to be removed. Once all of the decayed timbers have been removed, fungicidal treatments would be used to treat wall areas and new timbers.
A completely new length of support beam would be placed in two sections, using a halt lap joint or a resin connection joint. New back roof rafters would be fitted sitting on top of the large support beam, using bolt-on connections. Similarly, new ceiling joists and sarking back boards would be placed. The client would be recommended to fit all new guttering and frameworks, once Timberwise’s treatments and works have been carried out, this also includes the lead linings, and the completion of the roof coverings, making sure all of the area is watertight.
For the window lintels technicians would prop up all brickwork, above each window, clear out all decayed timber lintels and clean out all dry rot. New concrete lintels would then be fitted back into each area. These would be bricked and packed up, support props would remain in situ until these have become set before props are removed. Some windows were extremely decayed due to dry rot. An application of fungicidal treatment would be applied to the perimeter windows, to keep decay at bay. New windows would need to be fitted after treatment and works.
Fungicidal treatments would require application of the solution to each support hole as well as the surface area around the perimeter of the affected walls. All affected timbers would be renewed, and all contact surfaces would be coated with either a bituminous solution or two liberal coats of water-repellent fungicidal fluid and would be protected with LignaTek fungicidal gel. Finally, all joist ends would be capped or laid on PVC DPC membrane.
Results
Timberwise surveyors inspected the property and gave an efficient and professional report on its potential risks and the damages caused by an outbreak of dry rot fungus and moisture ingress as a result of damaged rainwater goods. Our client was given a list of recommendations for works to be carried out by Timberwise in the future.
Do You Want to Request a Survey?
Our dedicated and experienced team in Liverpool are ready to talk to you about your options for property preservation. Don’t hesitate to call 0151 244 1040 or you can request a survey online.
