Is your roof covered with clay tiles.
Roof torching mortar.
It is common for the torching to deteriorate and for pieces to fall away from the inside of the roof.
Traditional variations of a physical secondary barrier against wind driven snow and rain include reeds laid between the tiles and the battens and a coating of mortar known as torching to the underside of the tiles or slates.
The torching on clay tile roofs contributed to securing them in the days before nibs were added to hold them on the wooden battens.
In the days before roofing felt torching or lime mortar was used on the underside of tiles or slates to keep them in place and to prevent strong winds from getting under the tiles and lifting them.
Unusual for a house built in the thirties.
Impartial advice on damp and damp.
Mixing and making hot lime mortar.
The dangers of rusty iron in old buildings.
Timber oak or elm what not to do to a timber frame.
There are 2 usual variations of lime mortar iside the loft space if it is torched it is basically rendering the inside of the roof or semi torched is pointing to the battens.
This may applied as either a repair to hold slipping slates or pre emptively on construction.
What you describe is called torching which is the pointing up with hair mortar of the underside of the roof slates or tiles.
This system was commonly known as torching and was used before the introduction.
In the days before roofing felt torching or lime mortar was used on the underside of tiles or slates to keep them in place and to prevent strong winds from getting under the tiles and lifting them.
Instead a soft sticky mortar mix was used both to help secure the slates and also prevent draughts.
Traditional buildings did not have bituminous underfelt beneath the slate or tile roofs.
Goodwill feb 27 2009.
Surveys of thatched roofing.
Both are there to stop wind.
Torching is still used today in heritage properties as an alternative to a modern breathable membrane.
A word about timber treatment.
Over the years this torching can crumble and break normally falling with a thud on the floor of the roof space during the middle of the night.
Originally the only recognised roof under coating was the application of sand lime mortar reinforced with animal hair applied to the headlaps of double lapped slates or tiles.
Torching is most commonly encountered to the underside of old stone slate roofs.
What materials should be used in old houses.