266 



THE BOOK OF THE LANDED ESTATE. 



Struts, 5 inches by 3 inches. 



Purlins, 7 5 



Small rafters, .... 6 3 



Ridge-pole, .... 8 1$ 



The queen-post truss is shown in fig. 96. It is more suited for greater 

 spans than either of those already described. Such a form of roof may 



safely be adopted up to spans of forty feet. The sizes of the different 

 timbers for a forty-feet span are thus : 



Wall-plates b b, 

 Tie-beam a, 

 Pole-plate c c, . 

 Ridge-pole d, . 

 Small rafters e e, 

 Rafters//, 

 Straining-beam g, 

 Queen-post h h, 

 Struts i i, 

 Purlins k k, 



6 inches by 6 inches. 



10 



5 

 9 

 4 

 6 

 8 

 6 

 4 

 6 



6 

 5 



4 

 8 



4 

 6 

 6 



4 

 4 



The pitch of the roofs varies with the material employed for cover- 

 ing them, tiles requiring a greater pitch than slates. Many architects 

 adopt the plan of having a roof for slates one-fourth the length of 

 the total external width of the building, and for tiles they allow one- 

 third. 



Iron rods are now taking the place of king and queen posts in many 

 instances, and corrugated iron is also recommended as a covering for roofs. 

 I have not had much experience with it ; but from what I have observed, 

 I find it very liable to corrosion, and, in my opinion, it will not last so 

 long as slate. 



Felt has also been employed as a covering for roofs. We have used it 

 on this estate ; and from what I have seen of it, can state that it is at 



