Should I repair or replace my slate roof

[Alastairreid]

Thank you. What are my options now in that case

I'm sure you know the answer to that question.
It needs stripped and done properly ..by roofers this time.

 

[^woody^]

"What I lack in knowledge, I make up for with enthusiasm" does not always work out.

 

[datarebal]

It does need stripping and a re slate. it does not need CDRS or slate hooks.
it needs the correct size batten set at the correct gauge then slates refitted correctly.
Roof pitch is low so that should be taken into consideration.
The top of each slate should sit half on the batten above.
I hope you have not paid.

the original roof would have outlasted this Spanish slate roof fitted in this manner

 

[JackK]

It does need stripping and a re slate. it does not need CDRS or slate hooks.
it needs the correct size batten set at the correct gauge then slates refitted correctly.
Roof pitch is low so that should be taken into consideration.
The top of each slate should sit half on the batten above.
I hope you have not paid.

the original roof would have outlasted this Spanish slate roof fitted in this manner

I have paid. They did the work in one and half days. Total cost £2,000 labour only.

The original roof was all powdered and crumbling and cracked and had been repaired many times and was still leaking so it had to be changed

I’m disappointed it did not sit on the roof batten above but each tile was nailed into the batten

 

[JackK]

For anyone interested video of roof

 

[JackK]

Because pictures say a thousand words here was the original roof which was powderey and cracked

 

[datarebal]

The new roof is wrong. There is virtually no head lap . The underlay is keeping water out for now.
It won't last long .
Ask for your money back .
I'm being honest , don't kid yourself it's ok .

 

[JackK]

headlap is 50mm and its london so sheltered location. I want to understand scientifically what is wrong with this

So far three issues have been raised

1) Headlap? - Seems fine at 50mm - The tiles were predrilled so would have had to drill new holes
2) Top of tile not on batten - True but he did explain that if it was on top the slate above would have movement and be subject to crack and I believe he has doen roofs before and came reccomended
3) Flashing should have been done in lead and not slate and conrete - That is true
4) pointing is messy

Out of interest how much would a "proper" roofer have charged for this? And judging what I see on here most roofers also make a mess

 

[datarebal]

Roofs leak in London .
The guys don't have a clue about slate works and how they work.
50mm head lap is not enough at that roof pitch.
Who supplied the slates?

you have been ripped off.

 

[robinbanks]

Gauging the battens so the tops of the tiles didn't sit half on reduced your headlap by about a batten's width

he did explain that if it was on top the slate above would have movement

It's not true, I'm afraid. The bottom row needs careful setup to start the kick-up then every other row up the roof is angled such that the slates lay flat on each other but at a shallower angle than the roof is. They don't move and they don't bend.

Regard this image:

if nailed so the slates can lift, the wind will lift them, causing several problems:

* repeated lifting over the years (nature is relentless) wears out the slate or the nail and will eventually result in the slate coming off the roof
* savage lifting may break the slate; the slate pivots around the nail and there's a lot of leverage the large flap of slate between nail and base can apply to the small flap between nail and top of batten it's nailed to. Slate either pulls the nails out, the heads pull through the slate or it breaks along the nail holes
* unlike a human, Mother Nature can lift all the slates on a roof at the same time. Lifting the top row can break your ridge tiles off
* wind accompanies rain, and a wind direction that lifts your slate also drives rain under them

The previous slate roof was also lapped like this apparently

They said?

Headlap? - Seems fine at 50mm - The tiles were predrilled so would have had to drill new holes

Indeed, the pre drill dictates the gauge and, together with the length of the slate, the headlap. If you wanted a particular headlap, eg to cope with a very exposed location, you'd either buy slates predrilled in a particular place or you'd hole them yourself with a dedicated tool. As noted, setting the batten above this row so that this row's slates aren't half on it does rob you a batten's width of headlap; every slate is nailed to the centre of a batten, so to move the batten above up a bit means those slates nailed to it also move up by the same amount i.e. they overlap those immediately below by half a width less, but the headlap comes from the second-above row..

 

[JackK]

Gauging the battens so the tops of the tiles didn't sit half on reduced your headlap by about a batten's width


It's not true, I'm afraid. The bottom row needs careful setup to start the kick-up then every other row up the roof is angled such that the slates lay flat on each other but at a shallower angle than the roof is. They don't move and they don't bend.

Regard this image:

View attachment 327165

if nailed so the slates can lift, the wind will lift them, causing several problems:

* repeated lifting over the years (nature is relentless) wears out the slate or the nail and will eventually result in the slate coming off the roof
* savage lifting may break the slate; the slate pivots around the nail and there's a lot of leverage the large flap of slate between nail and base can apply to the small flap between nail and top of batten it's nailed to. Slate either pulls the nails out, the heads pull through the slate or it breaks along the nail holes
* unlike a human, Mother Nature can lift all the slates on a roof at the same time. Lifting the top row can break your ridge tiles off
* wind accompanies rain, and a wind direction that lifts your slate also drives rain under them


They said?


Indeed, the pre drill dictates the gauge and, together with the length of the slate, the headlap. If you wanted a particular headlap, eg to cope with a very exposed location, you'd either buy slates predrilled in a particular place or you'd hole them yourself with a dedicated tool. As noted, setting the batten above this row so that this row's slates aren't half on it does rob you a batten's width of headlap; every slate is nailed to the centre of a batten, so to move the batten above up a bit means those slates nailed to it also move up by the same amount i.e. they overlap those immediately below by half a width less, but the headlap comes from the second-above row..

Thank you. This forum is full of knowledge.

I tried my best to learn about roofs before I supervised the project being done but it’s not so straight forward and a lot of details

The only comfort I have is that there are a lot of roofers who are just useless.

The job I have done is not perfect and

1) the slate and a half tile at bottom was not done instead they used two whole slates

2) the eaves drip tray sits on top of the membrane

3) the verge overhang is 20mm and should have been 50mm

4) the slate headlamp is 50mm and should be 75plus

5) the flashing should have been in lead

All in all it’s not brilliant but I do hope it’s not terrible. If it lasts ten years I will be happy.

Storms yesterday in London and heavy rain and tiles are fine and no wet patches Inside

Not much I can do now. If I don’t pay them likely to have door kicked in. They tried their best

 

[Harry Bloomfield]

2) Top of tile not on batten - True but he did explain that if it was on top the slate above would have movement and be subject to crack and I believe he has doen roofs before and came reccomended

I am not a roofer, but even to my unskilled eye - the tiles lower ends should not be able to be lifted, rocking on the nail and batten. The first time the wind blows, it will be quite hilarious watching those tiles flap up and down. You say 'he has done rooves before' - it's obviously no guarantee that he knows what he is doing.

Even I understand, the top edge of each tile, must sit partially on the batten above it, to prevent it rocking. You need to get him back, and explain to him, with the benefit of this discussion, what he needs to do to rectify the roof properly.

 

[diy_fun_uk]

I'm still part wondering if this is a wind-up. To the OP, people on here who have direct experience of roofing and folk like me who take a keen interest in things like roofing (yes sad I know!) have advised you parts of the installation are wrong, perhaps one of the biggest things being tiles not seated on the battens correctly. You yourself showed how easy it was to lift the tiles however if the location is generally secluded most of the time with little or no exposure to high winds then it might be fine. And yes you might get x years out of it.

However, ultimately the roof wasn't installed correctly. I also find this comment quite interesting:

... Not much I can do now. If I don’t pay them likely to have door kicked in. They tried their best ...

I thought you'd used these guys many times? Have you not therefore built up quite a good working relationship with them? Not sure I'd want to use tradespeople that I thought might kick my door in if there was some sort of dispute.

 

[Harry Bloomfield]

Not sure I'd want to use tradespeople that I thought might kick my door in if there was some sort of dispute.

I only spotted that line, after you pointed it out. In that case, I can understand the OP being concerned complaining about the work, but he has to take a stand.

 

[datarebal]

fwiw now, pre holed yes , they have just nailed into wrongly positioned battens. its rubbish on all counts.
live with it if you must.. until a ceiling comes down.