Low pitch, slate roof leak

[fatsheep]

Hi Folks,
I really appreciate you all taking the time to try to help me out.
I'll try to address some points;
This is what we started with re roof.

The building is not listed and I was told building regs was ok as it was a replacement of the roof that was already there. (We took the slates off to stop them crashing to the floor).
I didn't need planning for the kitchen as the officer accepted that the house was all one building.
The kitchen wall that you see in the picture had next to no foundations the builder built a new wall inside it, with foundations and tied the two together.

Breathable membrane was used.

I think there would be enough room to drop the wall(s) at the front but this would raise the back of the roof over the main house wouldn't it? The idea of a valley between the two is very clever but I can't see it being allowed. Also, that would presumably mean everything inc electrics in the ceiling, plaster etc would need to be redone.

You are quite right, I haven't actually asked about different roof coverings I've just assumed. If there is a chance this would work I shall ask on Monday. I'm told by someone in an even higher site, that they boarded over their shallow roof with weather board under the slates and this has worked for them. I've seen a system http://www.slecladding.co.uk/ondutile.htm that is something like that as well.

I have a specialist coming up on Sunday and I'll pass on his comments.

It is a very special house in a special place. I know that I'll have to spend to put it right but at this point in the build (All but finished) there is no spare money.

Once again I thank you guys for taking the time to look at my problem. I know that some of you must be thinking that its my own fault for not checking things properly and you are proberbly right. In my defence, I am just a shop keeper and I employed a builder to get the thing right.
Cheers Again
David G

 

[Feltwell]

Hi David, will post more up later but.......

I know that some of you must be thinking that its my own fault for not checking things properly and you are proberbly right. In my defence, I am just a shop keeper and I employed a builder to get the thing right.

I don't think anyone on here would judge you in that way. Dealing with old buildings is very much a learning experience and is something that I think everyone on here would agree does not stop, ever! You gain knowledge gradually - I have good knowledge in a very small number of areas and zero in many, many more! Similarly finding good tradesmen for those jobs that are just too big or complicated for you to tackle yourself is not easy and is something that you learn how to do better over time, often only after a couple of bad experiences.

If you came on here and said that you were replacing all your windows with UPVC and how much would you get if you sold those stone slates so you could replace them with interlocking concrete tiles, you might get a slightly different welcome!

 

[worms]

Sorry if I have mis-read something above, but you can clearly see in the first pictures the old roof line which would have given an adequate fall to the roof and this is confirmed by the work-in-progress pictures that show the old roof line. So it looks like whoever decided to raise this, but not take into account the required fall for a slate roof is to blame!

 

[Feltwell]

The pitch has been reduced, but I'm not convinced that even at the old pitch it would have been leak free - it still can't have been more than 15 degrees or so. If it was just an animal shelter then I guess a little bit of leakage in extreme conditions would not have been a great problem. Your builder must take some responsibility though, if he didn't warn you of any potential problems - anyone with experience of doing roofing work should know that this pitch wouldn't work.

I think there would be enough room to drop the wall(s) at the front but this would raise the back of the roof over the main house wouldn't it?

No - where your kitchen roof joins the main building stays at the same point, just the front wall level drops. This would of course compromise the headroom inside the kitchen, your call on if this is acceptable or not.

Also, that would presumably mean everything inc electrics in the ceiling, plaster etc would need to be redone.

Changing the pitch of the roof by dropping the front wall means your exisiting kitchen roof has to come off completely - the whole thing, supporting timberwork, ceiling and all. If you've a nice fitted kitchen now installed then it means you have a period with only a temporary roofcovering and, to be honest, a high chance that something will get dropped into the kitchen and damage it. Constructing a new "flat" roof underneath the tiles probably means the same thing. You may be able to construct a new ridged roof on top of the exisiting timberwork and leave your existing ceiling in place, but that changes the external roofline dramatically so as you say you may well not get permission.

Replacing the tiles with corrugated iron means much less disturbance - as your existing timber roof structure is supporting all those stone slates, it will have no problems with a few sheets of wriggly tin! The slates come off, insulation is added if neccessary, the tin sheets go on, then finishing jobs like lead flashing to main house wall and finishing off the eaves. No need to take your kitchen ceiling down - so much, much less disturbance (& cost as it's much quicker). Your kitchen ceiling plaster will almost certainly crack due to the disturbance to the roof structure whilst the work is being done, but that's only a decoration job - wait until it's done then rake out & fill the cracks and repaint the ceiling.

I'm told by someone in an even higher site, that they boarded over their shallow roof with weather board under the slates and this has worked for them. I've seen a system http://www.slecladding.co.uk/ondutile.htm that is something like that as well.

At a very (very!) quick glance that looks ideal and may solve your problem, enabling you to retain your existing roof structure and the slates. A couple of points spring to mind -

- Is it OK with the weight of your stone slates? They must be considerably heavier than most roof coverings.
- This will increase the height of your existing roof. In your pictures there is very little clearance indeed between the slates on your kitchen roof and the bottom row of slates on the main roof, where they join. Have you got enough room to use this system without having to drop the roof timberwork down? Perfectly possible to do but will add to the work & disruption & cost considerably.

Hope this helps, others may have different views!

Edit - just read that Onduline site a bit more, see the section on minimum pitches - that still looks to be more than you've got there. They do say you can go lower but with certain provisos. It would be helpful if you measured your roof pitch so you know what you're really dealing with - if trigonometry has long been consigned to the "never to be used again" part of your brain then just ask and I'll tell you what measurements to take!

 

[middi]

Having looked at your last photo it appears that your builder can build ok.
I know it is a bit late but he has made a mistake by not advising you that those stone slates will not accept a pitch smaller than 18 deg, this being the safer limit for such slates not thicker than 25mm.
Judging by the photo this would appear quite feasible. Actually it would not be a great deal to lower that roof line to the acceptable and safe limit by removing another thermal block or so from the lower end of the pitch and reposition the rafters at the lower level at that point. 2 good workers and three days labour should have that as good as new. Try to persuade the builder that you will contribute ( if you can of course) to the cost of rearranging the roof line. After all you appear to have warned him of your concerns and he, really, should have known better.

I would certainly try and keep the old slates
Good luck

Middi

 

[fatsheep]

Thanks, Midi, Feltwell, Penners.

Believe it or not we chose our builder carefully and as you say his work was mostly good. For a year we were happy with his, (pricey) work on a difficult job, sensitive renovation.
Fact remains that a roof that leeks is not much more use than no roof at all.

From what I understand, they built up one side of the wall to produce a more even roof, the barn slopes you see. However, to my eye it looks like the addition of the "false" wall flattened the overall pitch particularly at the gutter side where the problem is worse.

Thanks for the help
David G

 

[Penners]

David, let's be clear about this: the problem is not your fault. If you'd built the structure yourself, you'd be to blame. But presumably you felt that you needed someone with the necessary expertise to do the job properly, so you employed a builder. And he cocked it up.

I've no idea of the legal niceties in this, but I'd say that if you instruct a builder to build a roof, then the word "waterproof" is implicit in that instruction!

To my mind, the cheapest solution to this problem is going to be Feltwell's proposal that you use corrugated tin. But if you really don't like that idea aesthetically, then I think I would probably do what was suggested higher above: create what is effectively a proper, waterproof flat roof structure on your existing rafters, and then place a "cosmetic" slate roof on top of it. I still wouldn't use the thick slates that you have. I'd use normal thin slates.

Anything else is going to involve pulling down a great deal of what's already been constructed, and will be much more expensive.

 

[Schoolmarm]

However, to my eye it looks like the addition of the "false" wall flattened the overall pitch particularly at the gutter side where the problem is worse.

Thanks for the help
David G

I agree with you.
I am on the third roof on our small utility room as the stone just wanted to pull all the water inwards.

Last one involved dropping front wall and raising the bit near the house and we still only just escape that problem of each slate being flat. Our room is a lot smaller than yours though.

 

[Feltwell]

Believe it or not we chose our builder carefully and as you say his work was mostly good. For a year we were happy with his, (pricey) work on a difficult job, sensitive renovation.

Being charitable for a moment, we all make mistakes in both our professional and private lives, and builders are no exception to this. If the rest of the job he did was good, then what's important is how he responds to the problem. If he admits that it is his fault and takes steps to put it right then that, to my mind, is entirely satisfactory and is the mark of a good tradesman. Of course if he warned that the pitch may give a problem then that is totally different!

I have a friend who is a hard landscaper, a good one at that. He laid a customer's driveway with the fall going the wrong way - a stupid error and entirely his fault, it only came to light when the job was complete. He offered to relay the drive at no extra cost, but the customer insisted on taking legal action and wouldn't give him the chance to correct the problem. Luckily the magistrate agreed with my friend and rebuked the customer for not giving him any opportunity to correct the problem.

 

[Lime]

I know now that the pitch is too shallow, I know now that I was a fool to believe the builder. What I'm looking for is any alternative to lowering the front wall to increase the pitch. As well as the cost, I think this would mean the barn roof rising above the level of the house roof where they meet.

Raising the roof-join is a possibility but would involve a lot of extra work and may bring problems of its own.

Have you thought of lead in place of the tiles upon the outbuilding?

 

[Flyfisher]

I have a friend who is a hard landscaper, a good one at that. He laid a customer's driveway with the fall going the wrong way - a stupid error and entirely his fault, it only came to light when the job was complete. He offered to relay the drive at no extra cost, but the customer insisted on taking legal action and wouldn't give him the chance to correct the problem. Luckily the magistrate agreed with my friend and rebuked the customer for not giving him any opportunity to correct the problem.

My understanding is that the courts usually take a dim view of 'frivolous' litigation, as seems to be the case with this example, and quite rightly in my opinion. As you rightly say, mistakes happen and it's the response to a mistake that is the important thing. Frankly, your friend would get a good recommendation from me if it had been my driveway; mistake made, mistake readily admitted and mistake fully corrected at no additional cost - seems reasonable to me.

I'm not entirely sure what the point of legal action would be anyway, unless there was some claim for consequential damages, which I believe are pretty hard to enforce anyway. So that just leaves claiming damages to cover the cost of correcting the mistake to the driveway, which the builder had already offered. I guess there's no pleasing some people.

Here's a similar sort of tale. We had an extension built onto a previous house and I came home from work one day to find that the detailing of the brickwork above a window did not match the rest of the house. I worked myself up into a semi-rage thinking of all the arguments and counter-arguments for forcing them to correct the error even though I was worried that the detailing might not have been explicitly or clearly specified. I finally calmed down enough to ring the boss of the building firm that evening ready for a prolonged argument, but he just asked me what time I left for work in the morning and he would drop by about 20 minutes before then. I then had a night of broken sleep going over all the arguments and counter-arguments in my head.

The following morning he turned up at the agreed time, took one look at the brickwork and said 'well that's not very good is it? It doesn't match all the other windows at all. Don't worry, leave it with me'. I had hardly said a word. That evening, all the brickwork had been re-done and was a perfect match for the rest of the house. We subsequently used them for other works a few years later and recommended them to a few friends as well!

Mistakes can actually be a golden opportunity to really show a bit of customer care and commitment.

 

[LadyArowana]

Mistakes can actually be a golden opportunity to really show a bit of customer care and commitment.

I second that. I ordered some bathroom lights that were a "web special" from one of the electrical retailers and when they arrived the glass on both was in many tiny pieces. I told them and they had someone collect the broken ones and re-ordered. The next week they called me and said that they had decided to get the replacements delivered to their showroom so they could be checked rather than despatching them direct to me from the supplier. When they opened the boxes those were broken too, so they said they were very sorry but it would be a few more days. I thought that was much more sensible than sending me a box that rattled ominously that no one could be bothered to investigate. Since it had taken me ages to find something that I didn't find offensive that had the correct IP rating I was happy to eventually get them.

 

[fatsheep]

Hi Guys,
I totally agree with the points about giving people the chance to put things right. The firm who did my building have been back some 6 times to fix the roof but this hasn't worked and they now say they have "fullfilled their duty of care to me".

I'll try to keep this brief as I know that hearing people's builder stories can be as dull as ditch water.

We chose the firm as they understood what we wanted to do restoration wise and had done good work in the area.
Basically a team led by a site manager who we trusted and had good ideas and explanations. Evertything went well for a year then we got bad luck by the sack load.
Snow and rain held up the build. The site manager got ill befoore xmas and the firm decided to break for the hols early to allow him time to get better. Unfortunately he became very ill and the owner of the firm decided they couldn't continue without him and has ceased tradingn ot gone bust, they have assets they have just called it a day.
The owner of the firm is the guy who I've been dealing with since and has arranged the, in my opinion, poor attempts to fix the roof.

The attempts at a fix ranged from putting huge ammounts of silicon between the slates (which even I knew wouldn't work) to lifting the bottom two courses, slipping some blue/thin slate underneath, tapping the batton holes etc. They have moved from "don't worry we'll keep coming back until it's fixed" to "We havn't any more ideas"
They won't contemplate anything more structural as a way of sorting the problem.

Cheers David G

 

[LadyArowana]

Hi Guys,
I totally agree with the points about giving people the chance to put things right. The firm who did my building have been back some 6 times to fix the roof but this hasn't worked and they now say they have "fullfilled their duty of care to me".

I don't believe they have if the problem still exists and you have been promised no other fixing options or monetary compensation to allow you to rectify with another contractor.

 

[simon.d]

You could try laying the slates in a shallow lime mortar, or point them in situ with mortar to block the opportunity for water ingress. May do the trick and shouldn't change the appearance that much if done neatly..

 

[Lime]

Hi Guys,
I totally agree with the points about giving people the chance to put things right. The firm who did my building have been back some 6 times to fix the roof but this hasn't worked and they now say they have "fullfilled their duty of care to me".

I don't believe they have if the problem still exists and you have been promised no other fixing options or monetary compensation to allow you to rectify with another contractor.

When they start quoting such phrases you are near the end of negotiation.

Fit for purpose is the phrase they need to be reminded of.

 

[Lime]

You could try laying the slates in a shallow lime mortar, or point them in situ with mortar to block the opportunity for water ingress. May do the trick and shouldn't change the appearance that much if done neatly..

The classic bodge?
It won't last.

there is no magic solution for a roof that doesn't have much slope!
Either a material is used that can work in such circumstances (i.e. lead, zinc or sheet material of some sort) or the slope of the roof has to be altered.

 

[Schoolmarm]

They need to pay another contractor to lower the breeze block wall.

 

[simon.d]

You could try laying the slates in a shallow lime mortar, or point them in situ with mortar to block the opportunity for water ingress. May do the trick and shouldn't change the appearance that much if done neatly..

The classic bodge?
It won't last.

there is no magic solution for a roof that doesn't have much slope!
Either a material is used that can work in such circumstances (i.e. lead, zinc or sheet material of some sort) or the slope of the roof has to be altered.

I agree the pointing is a bit of a bodge, but laying the slates in a mortar could be quite robust if done well as upto a 1/2 foot of mortar would need to be penetrated for a leak to occur.. I agree though that some metallic sheet would be much better suited for this pitch, and will be route I will take to clad my lean-to's!..

 

[Feltwell]

The Onduline solution that David posted up is well worth investigating. My main concern there is that it must raise the roof slightly and the back edge of his kitchen roof looks very close to the bottom of the main roof tiles.

Other than that, without taking the roof off and lowering the wall it's either corrugated sheet or lead I reckon.