Adding a lat at bottom of roof

I am doing my first roof on my own.

Got everything water tight.

At the gutter i fitted a lat screwed onto the brick top. Nailed onto this baton were eaves trays which allow air to go underneath. So they raise up a little.

So what i have done at the eaves is change the starting height by 35mm approx.

I was advised by a mate to do this, but he didnt tell me it would have a knock on effect with my other lats.

So i started slating today and i already knew the next lat up needed to be doubled up in order to hold the tile well enough. So i raised this by 20mm ( planed a lat down before installing it).

Then on my next slate course i realised i had a gap again. So i realise i need to add a little height to the next 5 lats. Tomorrow i am going to get some lats ripped down to 10mm at my timber merchant.

Does anyone understand what i have done here and is it normal to build up the lower lats until the tiles blend in correctly ?

My mate said to use longer nails and just nail them in, but i wasnt happy that the tiles would not be sitting comfortably with support underneath them. As soon as you go on the roof with a ladder the lower section slates would just split.

I’m also about to undertake my roof...

Relief when that breather membrane goes down.

not sure exactly what you mean regarding the heights. The tile battens should all be in the same plane. (Height relative to the rafters)

this site is v helpful.

https://www.fixmyroof.co.uk/

When you take off the batons to put new back down, in my case i added an extra baton on the wall at the eaves. This raised the height of the roof my 35mm, so the other batons are now out of step with this starting baton. As i go up the roof this height difference is smoothed out, but lower down i need to raise a few of the batons so the tiles will fit on them fully. If not i will have fresh air underneath the tiles where they are supposed to contact with the lats. It is the case for 5-6 batons from the bottom.

Firstly I am no expert.

but Sounds to me like you need to increase all or none of the battens. Otherwise your always going to be chasing the height up the roof.

Its normal for the Lowest batten to be thicker. (The tilting fillet) which as I understand it should be the thickness of the tile batten plus the thickness of the slate and possibly a few more mm for good measure.

First row of Slates sit on Fascia board (approx 40mm above rafters)

I dont have a facia B Just screwed straight into the bricks.

Have you fixed a vent to the bottom battern if so remove battern an fix vent straight to brickwork as others have said you need 40 max no upstand for slates or you will be adding lathes untill you flatten out

I have the vent at the bottom with baton and i have had to build up the first 4 batons after this one to even out the pitch. Its worked out fine in the end. Got to the top today. Going a lot slower than i expected.

Any idea how long it takes a 2 man roofing team to do a one pitch roof of 28sqm. I still have to do about 1/4 of the slates, plus fit the ridges on mortar plus mortar up the edges and fit the coping stones on one side.

This is the roof before i started.