Cockrams Surveying Ltd recently undertook a survey in Falmouth. The property is likely to have been constructed around 1890 which most likely included a single storey solid brick and stone scullery to the rear. This was extended to the side in the 1950s or 1960s and most likely under government grant assistance that was available under the Slum Clearance Programme of that period whereby internal bathrooms and toilets were recognised as a necessity to improve general hygiene and quality of life.
This property had a double pitched, man-made slate covered roof with the rear single storey roof being of mono-pitched design. The rainwater provision to the main roofs was formed in a system of plastic gutters and downpipes. The main walls were rendered externally and plaster faced internally and were approximately 600mm thick which is consistent with random rubble fill stone and cob construction. The walls to the former scullery were of solid brick with a timber frame infill panel. The walls to the later bathroom extension were approximately 280mm thick which is consistent with cavity concrete block construction.
Apart from one slate being missing to the main front roof slope and a fairly minimal verge projection, the roof coverings did appear to be in good overall condition. The slates over the rear mono-pitched roof were also in fair condition although some of these were older fibre cement/asbestos slates. It was noted that the gable end of this end of terrace house was very exposed. Internally, it was noted that the gable end wall within the first floor bedroom had been dry lined with plasterboard. It was noted in the sitting room directly below that there was a damp stain at the junction of the ceilings and walls, which was checked with the aid of a moisture meter and dampness was found and particularly to the chimney breast.
It was noted externally that the verge cover slates have been removed and cement had been run up underneath the roof coverings. It is quite probable that this junction is not totally watertight and that the hessian reinforced bitumous felt, that has been fitted underneath the roof coverings to act as a secondary means of defence against rainwater penetration, has rotted where it would have been continued over the gable end wall. To overcome this problem, it would be considered necessary to strip the external render from the wall, if at all possible, and fit battens level with the gutter line up to the top of the gable wall to which a membrane and vertical slates could be fitted.
We also recommend that the roof coverings should be stripped back to the front and rear of the gable end and the roofing felt made good. In addition, the vertical membrane system should be designed so that it overlaps the repaired felt over the roof coverings and lead soakers or similar should have been fitted at the junction of the vertical wall and sloping roofs. This is a belt and braces approach but in this exposed location, we did consider that these works are necessary.
In addition and on the same property, it was noted that there are extensive areas of hollow render to the front. This is very likely to have held water between the impermeable cement render coat and random rubble fill stone and cob. We advised our client that the render should be stripped off and that the front elevation should be re-rendered in lime and decorated thereafter with a lime wash or modern microporous paint. We never recommend using Ordinary Portland Cement (OPC) or proprietary brands of masonry paint on stone and cob walls as this tends to trap moisture into the construction which increases internal humidity and dampness.