Underpinning key to future of Mere's Mouth toilet, surveys conclude
Two expert reports on the state of the Mere’s Mouth toilets in Diss both come to the same conclusion: without underpinning the foundations, the building does not have a long-term future.
Neither report says how much time would be left for the toilets without underpinning and no exact cost can be placed on it at this stage – it would depend on what was discovered as the work progressed.
One of the surveys says that it would start at £25,000, which it describes as “disproportionately high” for the size of the building.
It is estimated that piling would have to go down 20 metres to be effective – and it is pointed out that some of the piling of the neighbouring Diss Publishing building went down a further 10 metres.
The Diss Express understands that demolition would cost about £20,000, which would leave the town council with about £60,000 of the £80,000 lump sum South Norfolk Council pledged for refurbishment if the town took over responsibility for the toilets.
The £60,000 would depend on new toilets being built at the Mere’s Mouth, it is understood.
The Diss Express has now seen copies of both surveys, which were carried out by Frith Blake Consulting and the NPS Group.
The NPS report, compiled following a survey in 2015, says the original public convenience building was in generally a fair condition for its age. However, the evidence of ongoing settlement caused by poor ground conditions indicated that eventually “significant structural work” will be needed.
Although “two significant cracks” were identified, the building was still structurally safe, the report said, but required a “mini piling system” to stablise it.
If there was not enough money for the piling at this stage, the report advised the installation of monitoring discs and six monthly readings. It also detailed a five-year programme of repairs and replacements.
It noted that the toilets were an “important amenity” and the building would be “suitable for this existing use for many years to come” if its recommendations were carried out.
With the recommended work, it forecast a “life expectancy” of 50 years for the former tourist information centre which adjoins the toilets and 30 years for the toilets.
The Frith Blake report is based on a survey carried out in January last year. This also noted the “vertical displacement” which had been going on for years, although it did not appear to have had an impact on the overall stability of the structure.
“With adequate repairs and future maintenance, we would conclude that the structure can remain serviceable,” it notes.
“With the exception of the principal separation cracking, the condition of the walls, ceiling and roof (observed externally only) are in reasonable condition, suggesting the integrity of the foundations to each construction phase is maintained.
This further supports the conclusion that there is a gradual increase in consolidation on the underlying soils ... and that there is no localised loss of support to the footings.”
In its conclusion, the report notes that without remedial work, the defects will progress, although at what rate it is difficult to predict.
The only long-term solution was underpinning, but the report adds: “Given our experience of similar projects, the cost of the piling could be in excess of £25,000. This excludes the cost of other remedial work to repair the cracking of the walls.
“If the building is not underpinned, it should be acknowledged that there will be ongoing vertical and lateral movement. However, there are numerous repairs that could be undertaken to minimise any future maintenance costs.”
The report details the further repairs and divides them into a five and 10-year plan.