APPENDIX. 135 



" The trusses in the above table to be about ten feet apart, and the 

 commom rafters fourteen inches from centre to centre ; the feet of 

 the principal rafters, &c., to be secured to the tie beams by proper 

 wrought iron straps. 



" Joists having a bearing of from 10 to 16 feet, to be 2|- inches in 

 thickness, with 2-3rds of an inch in depth for every foot between 

 bearings, and from 16 to 24 feet, to be 3 inches in thickness, with 

 5-8ths of an inch in depth for every foot between bearings. 



" Trimmers and trimming joists to be at least half an inch thicker 

 than the common joists. Lintels to be generally 3 inches thick ; 

 those to all openings more than 3 feet 6 inches wide to have l| inch 

 additional depth for eveiy extra foot of opening ; all to be the full 

 width of the wall within the reveal, and to have 9 inches of wall 

 hold at each end. 



" For Stairs, risers and treads in no case to be less than one inch 

 thick ; treads not to be under 9 inches in width, and the rise not to 

 be more than 7-| inches from step to step. 



" For Eoofs, all purlins to be in long lengths, and to be placed on 

 the back of the principal rafters, and supported by blocks ; no rafters 

 or ties to be notched to receive them ; all joinings to occur over a 

 principal. 



" Where roofs are covered with duchess or countess slates, the same 

 should not be laid with a lap of less than 3 or 2^ inches ; each slate 

 to be fastened with two nails, the laths to be 2" X f 



" Nails for slating to be either copper, zinc, galvanised iron, or 

 nails dipped in oil when in a state of red heat. 



" The ridges, &c., in all cases to be either covered with lead (6 Ibs. 

 to the foot), proper ridge tile crest, set and pointed in cement, or 

 with patent slate ridging with roll, fastened with screws, and set in 

 oil putty. 



" Plumber. Flat gutters between roofs, &c., to be laid with lead 

 7 Ibs. to the foot, valleys with 6 Ibs. and flashings with not less than 

 5 Ibs. Cast-iron eaves guttering to be provided to the roofs of 

 nil buildings, with proper 3 inch down-pipes connected to drains to 

 carry off the water ; the guttering and down-pipes to be of metal, not 

 less than -^ of an inch thick ; to have two coats of paint before being 

 fixed, and at least one after, all joints to be put together with red 

 lead. The use of zinc for gutters between roofs, &c., will not be 

 sanctioned. 



"Painter. All woodwork, &c., usually painted both inside and 



