Strengthening roof prior to re-roof

[hvendlor]

replacing old slates with cement tiles(cost main issue) on a 19th century terrace. All roof timbers are sound, there's 4 huge purlins(3"x 9") sat in the end walls and no signs of deflection anywhere in the roof structure..... New tiles weigh a fair bit more than the old ones so want to be sure it's strong enough to take them.

Obvious thing seem to be to add some braces up top between the rafters, 3x2" secured with 4" nails?

 

[Regencyroofingipswich]

Looks pretty strong as is as long as the timbers are good but a bit of strengthening always helps.

You are on the right track about bracing the roof at the top although when we do it we use 4x2 and bolts.

 

[htgeng]

I wonder if the OP has got more than one quote for slate? Concrete tile roofs look naff if both neighbours on a terrace have tiles. Theres also the intersection with both sides which will be a weak point for any water ingress.