New roof on a full house refurbishment or is it War & Peace?

[frslam]

Hi all, Season's Greetings and all that! Where do I start? I'm refurbishing my old family home. I employed a roofing contractor and he agreed to purchase the materials on my behalf for which I provided all the correct order codes. The roof is approximately 140m2, job entails stripping lightweight concrete slates, fitting new membrane, fascia's, 5 x VELUX windows and re-slating. The price for all of this (not including scaffolding) was approximately £30k. The job was supposed to start mid to late October, allowing the roofing contractor to safely strip the roof before my new windows (£15.5k) were going to be installed.

 

My new windows were installed on the due date of 10th November but the roofing contractor spent the previous couple of weeks giving me excuse after excuse why he hadn't started yet. When he did get around to starting, I provided him with as many sheets of OSB as needed in order to protect the new windows before I headed off for a meeting. On my return, the roofer told me he had damaged a window (the biggest window in the house). I inspected the other 2 windows on that elevation and discovered that he had damaged all 3 windows, at a cost of over £1,700.00. At first he said he would pay for the damaged windows (which I naturally, secretly recorded him saying). I received the quote for the repair and relayed this to the contractor, he said "it is what it is..." before again confirming that he would be paying for the damage. He drove away from the site and after a few minutes he phoned me. He said "just calling to let you know that I won't be paying for the repair of your windows because your scaffolding is not 'up to spec' to protect the windows below it. All I could say in reply was, scaffolding's job is for access and safe working at height environment, not to protect windows. I also asked him why he never used a debris chute to safely discard old slates from the roof. Hi response was "well, where's your skip". (I didn't have one, it wouldn't fit and couldn't be positioned on site because of low overhead electric wires), but the tele-handler on site was used with a big bucket to load the old slates into anyway. 

 

The Roofing Contractor starts fitting VELUX windows into framing that had been previously carried out. All he had to do was drop them in and fix them to timber. Then the breathable membrane was installed and finally the slating started (no grading of slates was carried out). I inspected the roof while he wasn't onsite (which was most of the time), and the day before he was due to come back to site I sent him an image on an instant message platform. I needed to inspect the work carried out up until then because we had a storm hit us between the time he left the site and the time he was due to return. This was on a Sunday but we agreed that he'd work Sundays in order to get the job done before the worst of the weather hits us. He didn't actually show up on Sundays, or most other days either. I told him I was unhappy with the membrane fitment, not 'lapping' into the (Scot) Dry Verge channel like it's supposed to, in fact, sarking boards are visible between the membrane and the Dry Verge. His response was to tell me that he couldn't work for me anymore, that he would be in the following day to collect his things. Then came the threats of Court action from him. All I paid him up until this point was approximately £16k for materials and a joiner to work alongside myself. I have to cover myself so went up to inspect his work. The 'cheap' membrane he used on the roof had completely failed or was poorly installed, allowing the rain to soak right through the sarking boards, the water was beading on the inside of untreated timber sarking. The sarking boards aren't a major issue being relatively cheap and easy to replace, what was very concerning was the sheer amount of water coming in, soaking the sarking and all that water starting to soak into all of the rafters. The house had been constructed in the early 1970's and I'd be lucky if the roof timbers were treated at all (against water ingress damage). As it turns out, the contractor ordered the incorrect flashings for the VELUX windows, destroyed the cartons they came in before realising they were the wrong items, then telling me that they couldn't be returned now because the boxes they were in were damaged and not re-usable. I then have to spend another £1k buying the correct flashings ( I had already paid for all materials when they were ordered from JEWSONS). 

 

On discovering the wrong items were delivered, the Contractor telephoned the local JEWSONS to report it. They told him, which I heard as I was standing right beside him, that I had gone in to the local JEWSON Depot and changed the order. I did go in to the Depot but when I asked the staff about the order, they told me they couldn't discuss it with me because it was someone else's (the Roofing Contractor's) order. So I get the blame which should be impossible, going by their own policies, and the roofer destroys the cartons containing the materials, meaning they cannot now be returned.

 

I have plenty photographic evidence of all this. I also taken images from the slating side. There are images of the sarking and rafters taken 9 days after the roof membrane was installed, images of the membrane to Dry Verge fitment and images of the slate installation (which I think isn't great, but am I being too fussy? The difference in position (course height) of the slate upper left of the image with the slate to the right of it is approximately 8-9mm followed by another 5-6mm height difference again to the next slate)

 

 

[Andehh]

Time for a new roofer, or start resolving yourself I’m afraid. 

 

Part of self building is knowing you get good trades, and (expletive deleted)ing shit hole bastard crooked ones (delete as required). We got lucky in having so many good ones... But I would piss on the electrician if he was on fire.

 

Edited Thursday at 00:28 by Nickfromwales
Such an awesome post can’t have typos. Salute!

[Gus Potter]

The key qeustion here is do you still own the Contractor money and if so how much? That will drive the rest of the conversation. 

8 hours ago, frslam said:

Then came the threats of Court action from him.

Make sure you write to the Contractor and confirm that he has confirmed he is walking away form the job. 

 

I used to be a building Contractor in my last life, once I had a customer that was basically an out and out chancer and I wanted to leave the job. My QS told me.. on no account Gus chuck your tools in the van and walk off site as you will get absolutely hammered! The law rests firmly on the domestic Client side and they have an Architect who will back them up and they won't want to put themselves in the firing line. 

 

Make sure when you write to the Contractor, use the postal method also, don't just rely on email. This is a key step. If he is using wats app / text then say I've sent a letter and email to you, keep a copy. 

8 hours ago, frslam said:

which I naturally, secretly recorded him saying

Ah.. best not to mention this anymore, it kind of undermines you taking the high ground.

 

8 hours ago, frslam said:

I inspected the roof while he wasn't onsite

Ah... now the first response from Contractor on the defensive is to say "its my site" and you are not authorised to access the scaffolding and you inspected the work illegally! I have actually had similar from a major warranty provider where they asked me how I got record photographs without accessing the scaffold. I told them I'm an SE so qualified to make an assessment of your scaffold. I consider this a matter of saftey and it turned out I was right also, your ticket was out of date so lets start from here! Your case is a little different, but if the Contractor has previously allowed you to go up the Scaffold without supervision at all times, induction, then they are pretty much stuffed. 

[frslam]

27 minutes ago, Gus Potter said:

The key qeustion here is do you still own the Contractor money and if so how much? That will drive the rest of the conversation. 

Make sure you write to the Contractor and confirm that he has confirmed he is walking away form the job. 

 

I used to be a building Contractor in my last life, once I had a customer that was basically an out and out chancer and I wanted to leave the job. My QS told me.. on no account Gus chuck your tools in the van and walk off site as you will get absolutely hammered! The law rests firmly on the domestic Client side and they have an Architect who will back them up and they won't want to put themselves in the firing line. 

 

Make sure when you write to the Contractor, use the postal method also, don't just rely on email. This is a key step. If he is using wats app / text then say I've sent a letter and email to you, keep a copy. 

Ah.. best not to mention this anymore, it kind of undermines you taking the high ground.

 

Ah... now the first response from Contractor on the defensive is to say "its my site" and you are not authorised to access the scaffolding and you inspected the work illegally! I have actually had similar from a major warranty provider where they asked me how I got record photographs without accessing the scaffold. I told them I'm an SE so qualified to make an assessment of your scaffold. I consider this a matter of saftey and it turned out I was right also, your ticket was out of date so lets start from here! Your case is a little different, but if the Contractor has previously allowed you to go up the Scaffold without supervision at all times, induction, then they are pretty much stuffed. 

I still owe all of the Labour which is only due on completion, £11.5k. As far as any trades are concerned it's my scaffolding. I set it up for myself to replace all fascia and soffits after stripping the old out. All the roofing contractor did after I finished that was to lift the scaffold up a level. I would have slated the roof myself but I got a nasty kick back from the rip snorter a month ago (2 fingers barely hanging on) when carrying out Joinery inside the house. My main reason for posting this on here was to see what you guys thought, particularly if I potentially had a reason to be unhappy about the standard of the works carried out going by the images provided, or am I wrong? Sometimes, stuff like this could be quite subjective, other times not

[Gus Potter]

3 minutes ago, frslam said:

I got a nasty kick back from the rip snorter a month ago (2 fingers barely hanging on)

Hope you can get your hand sorted out. That sounds like a bad accident, don't blame yoursefl, it could happen to anyone. 

 

To business.

 

9 minutes ago, frslam said:

My main reason for posting this on here was to see what you guys thought, particularly if I potentially had a reason to be unhappy about the standard of the works carried out going by the images provided, or am I wrong? Sometimes, stuff like this could be quite subjective, other times not

I think you likely have enough to evidence against the standards, so not subjective. Unless you have over egged your post. 

 

But you have not provided that many photographs. Your sarking boards are treated, so not rotting,  so I would not want to hang my hat on that as as a basis. But here is a question. If the roof has a breathable membrane then we need to have gaps between the sarking boards. I specify 100 mm wide boards with a 5.0 mm gap. You don't seem to have this. A competent roofer should know that this is a general requirement and check that the membrane is ok and the sarking gap. 

 

As an art of slating the slates at the verges are not tailed to shed the water back towards the roof. But you have plastic verges, just a symptom of decreasing skill level in the slating trade. 

 

My gut feeling is that if I and others on BH were to look under the bonnet we would come up with evidence that supports the arguement that you should not pay this contractor the balance. I trust you have photos from the inside of the roof. Lets have a look at the Velux trimming and so on. What nails has the roofer used? Let us know so we can check they have used the right ones. How close are you to the sea? 

 

Legally what you might want to ( I'm not a Lawyer so don't come after me!) is confirm if the Contractor intends to return or not. If they say they are going to return then you need to spell out the defects you want addressed, at their expense and when they are going to do that. You might want to say that if you can't agree then you will both agree on an independent arbitor. 

 

Now there is a good chance that the Contractor won't come back as they have chucked their toys out the pram. But you have to go through the process so protecting yourself. The contractors wife may be a Lawyer and work pro bono. 

[frslam]

24 minutes ago, Gus Potter said:

Hope you can get your hand sorted out. That sounds like a bad accident, don't blame yoursefl, it could happen to anyone. 

 

To business.

 

I think you likely have enough to evidence against the standards, so not subjective. Unless you have over egged your post. 

 

But you have not provided that many photographs. Your sarking boards are treated, so not rotting,  so I would not want to hang my hat on that as as a basis. But here is a question. If the roof has a breathable membrane then we need to have gaps between the sarking boards. I specify 100 mm wide boards with a 5.0 mm gap. You don't seem to have this. A competent roofer should know that this is a general requirement and check that the membrane is ok and the sarking gap. 

 

As an art of slating the slates at the verges are not tailed to shed the water back towards the roof. But you have plastic verges, just a symptom of decreasing skill level in the slating trade. 

 

My gut feeling is that if I and others on BH were to look under the bonnet we would come up with evidence that supports the arguement that you should not pay this contractor the balance. I trust you have photos from the inside of the roof. Lets have a look at the Velux trimming and so on. What nails has the roofer used? Let us know so we can check they have used the right ones. How close are you to the sea? 

 

Legally what you might want to ( I'm not a Lawyer so don't come after me!) is confirm if the Contractor intends to return or not. If they say they are going to return then you need to spell out the defects you want addressed, at their expense and when they are going to do that. You might want to say that if you can't agree then you will both agree on an independent arbitor. 

 

Now there is a good chance that the Contractor won't come back as they have chucked their toys out the pram. But you have to go through the process so protecting yourself. The contractors wife may be a Lawyer and work pro bono. 

OK. When the contractor told me that he could no longer work for me because I criticised the membrane fitment in relation to the dry verge, he stated that he would be on site the next day to collect his tools. He did arrive and took all his tools away the following day. 

 

The timbers in the roof are from the early 1970's, the sarking is not so much of a worry, that's 10 a penny and easy to swap but the level of water in them and they're soaking into rafters, that's a different kettle of fish. Not sure what the level or standard of treatment was available almost 60 years ago.

 

Didn't need to over egg any of it,  unfortunately. 

 

Velux fitment is woeful. He deleted the insulated collars that came with the flashings kits and opted instead for a 10mm trimmer gap and expanding foam. The Velux was also caked around the outer edges with sealant, my opinion is that is unnecessary, Velux kits are expensive and designed to prevent any leaking.

 

The images from inside the roof were taken 9 days after the membrane was installed and expected to be like that until mid January when the correct velux flashings would arrive. The winters in the Highlands beside the West Coast are rough and I feel that a lot of damage could occur.

 

 

 

 

[frslam]

1 hour ago, Gus Potter said:

Hope you can get your hand sorted out. That sounds like a bad accident, don't blame yoursefl, it could happen to anyone. 

 

To business.

 

I think you likely have enough to evidence against the standards, so not subjective. Unless you have over egged your post. 

 

But you have not provided that many photographs. Your sarking boards are treated, so not rotting,  so I would not want to hang my hat on that as as a basis. But here is a question. If the roof has a breathable membrane then we need to have gaps between the sarking boards. I specify 100 mm wide boards with a 5.0 mm gap. You don't seem to have this. A competent roofer should know that this is a general requirement and check that the membrane is ok and the sarking gap. 

 

As an art of slating the slates at the verges are not tailed to shed the water back towards the roof. But you have plastic verges, just a symptom of decreasing skill level in the slating trade. 

 

My gut feeling is that if I and others on BH were to look under the bonnet we would come up with evidence that supports the arguement that you should not pay this contractor the balance. I trust you have photos from the inside of the roof. Lets have a look at the Velux trimming and so on. What nails has the roofer used? Let us know so we can check they have used the right ones. How close are you to the sea? 

 

Legally what you might want to ( I'm not a Lawyer so don't come after me!) is confirm if the Contractor intends to return or not. If they say they are going to return then you need to spell out the defects you want addressed, at their expense and when they are going to do that. You might want to say that if you can't agree then you will both agree on an independent arbitor. 

 

Now there is a good chance that the Contractor won't come back as they have chucked their toys out the pram. But you have to go through the process so protecting yourself. The contractors wife may be a Lawyer and work pro bono. 

Now, the sarking usually has a 3 to 5mm gap on most boards but they are so full of water that they have expanded a bit. I know the images look a wee bit glossy like well treated timber, but that's not the case - they are very wet. Gently pushing your thumb into the timber sends quite a bit of water down your sleeve

 

The rafter framing/trimming for Velux was carried out myself under instruction, the roofer quoted all opening sizes to me as I never had the windows on site. I only realised afterwards that the openings didn't allow for the insulated collars. This is evidenced by dimension details forwarded to me by the roofer. I opted for level top and plumb lower reveals.

[frslam]

12 hours ago, Gus Potter said:

The key qeustion here is do you still own the Contractor money and if so how much? That will drive the rest of the conversation. 

Make sure you write to the Contractor and confirm that he has confirmed he is walking away form the job. 

 

I used to be a building Contractor in my last life, once I had a customer that was basically an out and out chancer and I wanted to leave the job. My QS told me.. on no account Gus chuck your tools in the van and walk off site as you will get absolutely hammered! The law rests firmly on the domestic Client side and they have an Architect who will back them up and they won't want to put themselves in the firing line. 

 

Make sure when you write to the Contractor, use the postal method also, don't just rely on email. This is a key step. If he is using wats app / text then say I've sent a letter and email to you, keep a copy. 

Ah.. best not to mention this anymore, it kind of undermines you taking the high ground.

 

Ah... now the first response from Contractor on the defensive is to say "its my site" and you are not authorised to access the scaffolding and you inspected the work illegally! I have actually had similar from a major warranty provider where they asked me how I got record photographs without accessing the scaffold. I told them I'm an SE so qualified to make an assessment of your scaffold. I consider this a matter of saftey and it turned out I was right also, your ticket was out of date so lets start from here! Your case is a little different, but if the Contractor has previously allowed you to go up the Scaffold without supervision at all times, induction, then they are pretty much stuffed. 

I would just like to add, I didn't secretly record the first conversation when the roofer admitted to breaking my windows and offering to pay for the damage. I didn't record the next conversation when he told me why he wouldn't be paying to repair/replace the damaged windows, but because of his behaviour, this is why I had to strike up subsequent window conversations with him in order to cover myself. It's actually hellish that it had to come to that to be honest

[frslam]

On 17/12/2025 at 23:24, Gus Potter said:

Legally what you might want to ( I'm not a Lawyer so don't come after me!) is confirm if the Contractor intends to return or not. If they say they are going to return then you need to spell out the defects you want addressed, at their expense and when they are going to do that. You might want to say that if you can't agree then you will both agree on an independent arbitor. 

 

Now there is a good chance that the Contractor won't come back as they have chucked their toys out the pram. But you have to go through the process so protecting yourself. The contractors wife may be a Lawyer and work pro bono. 

The contractor is definitely not coming back. His standard of workmanship is not up to scratch, he continually referred to the Roofing Membrane as 'Roof Shield' which I was initially happy with, so that's what I thought he was installing. I know Roof Shield is a premium product and it's all I would use in the west Coast of the Highlands. Problem was, when he said 'roof shield' he was meaning it as a generic term, (like people who call a vacuum cleaner a 'hoover'), and he installed 'Corotop' (poorly). He billed me £500.00 for the Membrane which is normally just over £50.00 a roll (less than 5 rolls) but priced it as the (much) more expensive Roof Shield, but he kept referring to it as 'Roof Shield'. It has now cost me another £1,000.00 to strip the 400 odd slates off the roof and install actual Roof Shield because it's got to stay like that until the middle of January 2026 when the correct Velux Flashings are available (another thing he totally screwed up, the order was in his name and he stored the boxes in such a way that they were destroyed by rainwater, but I had to pay for the materials before they were delivered by JEWSONS. By the time he realised that he ordered the wrong type of Flashings to be delivered, the cartons they were in were destroyed at a cost of nearly £1,000.00 and were un-returnable.

 

 

[Mr Punter]

Is it now the case that the roof is correctly membraned by others, Velux properly fitted and you are waiting on the Velux flashings to complete the roof?

[frslam]

4 minutes ago, Mr Punter said:

Is it now the case that the roof is correctly membraned by others, Velux properly fitted and you are waiting on the Velux flashings to complete the roof?

Yes. The contract for the roof stipulated Roof Shield. He installed Corotop which is about half the price of Roof Shield (IMHO there's a reason why there's such a price difference) but he was charging me the price of Roof Shield. So I had to remove over 400 slates to re felt the roof, then it was re-covered in what was supposed to be used.

[Mr Punter]

So have you just parted ways, calling it quits, or is one of you wanting some money from the other?

[markc]

On 17/12/2025 at 22:53, frslam said:

nasty kick back from the rip snorter 

Now that’s a term I haven’t heard in many years. We always called the big Makita a rip snorter (used for cutting big glulam beams

[frslam]

1 hour ago, Mr Punter said:

So have you just parted ways, calling it quits, or is one of you wanting some money from the other?

He wants money for work carried out to date, around 5 grand but I class his work as totally substandard including wrong membrane and incorrect fitment, poorly fitted slates etc. He caused over £1,700 worth of damage to windows and blamed me for not using scaffolding to protect them, cost me £1,000 to de slate what he'd done and re felt with the correct membrane (we had agreed roof shield - in writing, he fitted corotop),  he cost me £1,000 when he destroyed the boxes containing velux flashings for 6 windows (doubles and singles) meaning they could not be returned. He missed out under eaves slate, laid some poor slate because he never graded them at all

[Nickfromwales]

3 hours ago, frslam said:

He wants money for work carried out to date, around 5 grand but I class his work as totally substandard including wrong membrane and incorrect fitment, poorly fitted slates etc. He caused over £1,700 worth of damage to windows and blamed me for not using scaffolding to protect them, cost me £1,000 to de slate what he'd done and re felt with the correct membrane (we had agreed roof shield - in writing, he fitted corotop),  he cost me £1,000 when he destroyed the boxes containing velux flashings for 6 windows (doubles and singles) meaning they could not be returned. He missed out under eaves slate, laid some poor slate because he never graded them at all

Tell him to get (expletive deleted)ed. 

[Andehh]

Just as a care point, from a total layepersons point of view those slates look neat, lined up and normal. You'd need to explain and evidence what's wrong with them. 

[frslam]

9 hours ago, Andehh said:

Just as a care point, from a total layepersons point of view those slates look neat, lined up and normal. You'd need to explain and evidence what's wrong with them. 

is that the image taken from the verge? If you look at the broken slate and half, the second course of slates above that should give the slate and half a double cover but the broken top left corner goes down so far that it wouldn't be that way, just take a line across from the highest slates. I might be being picky but it's my £30k that's re-roofing the house, I feel that I'm paying premium prices but not getting the product to match. On the image above,  where you can see the eaves course, a slate (or half slate) is missing altogether where there was no nail puncture in the membrane or on the eaves felt, so it was never installed. Ironically that corner of the house is looking at the South Westerly direction and gets the prevailing wind. Further, this is CUPA Heavy 3's being installed, all the eaves slates were installed with 1 nail per slate, according to CUPA, 2 nail fixings per slate should be used. Even if they didn't recommend that, I live in the North West Highlands, it's strongly advisable to double nail all slate courses including eaves courses

[frslam]

9 hours ago, Andehh said:

Just as a care point, from a total layepersons point of view those slates look neat, lined up and normal. You'd need to explain and evidence what's wrong with them. 

I stripped the 400 odd slates off that the slater had installed because I was unhappy with the membrane and to be honest with you, with the slating in general. He said that he wasn't going to grade the slates, that they were good enough. I disagreed. While stripping the slates, I found some slates on the higher courses were way more than the 20% tolerance thicker than slates fitted below them. I know it's tricky getting to show this in a photo because the higher the slates are, the more of the riven edge you see, so it's hard to tell on this image but I just didn't like it. I said in a previous message that I expected the quality for £30k, forgot to mention, that figure doesn't include the several £thousand's for the scaffolding

[Nickfromwales]

£30k is a lot of dosh for mediocre work and then having the house damaged too is just shocking.

[frslam]

38 minutes ago, Nickfromwales said:

£30k is a lot of dosh for mediocre work and then having the house damaged too is just shocking.

Thank You. the guy was unbelievable. I paid all materials up front, including slates. On the quotation it says 'Materials for Roof - £8,500.00' (plus VAT). When the slates arrived I told him there were about 1,000 short. He didn't expect me to count them. He told me he had a pallet of slates in his yard that he could sell me for £1.60 each. Couldn't believe it, trying to pull a fast one! I said no way! I've just paid £8,500.00 plus VAT for materials, I gave him the dimensions which would allow 10% ish over the quantity needed to slate the roof. I then sent a screen shot taken from SMS Texts, reminding him that I gave him all roof dimensions for ordering materials. His reply to that? Are you telling me that you're not paying for Roof Shield because that's like another £500? I'm no Einstein but FFS, he's about as bright as a bloody eclipse! The conversations were on WhatsApp, I had to block him so he couldn't contact me to delete the messages. I have written it all down, from WhatsApp or SMS conversations, looks like I'll have to take legal action to recover costs for damaged windows, damaged velux flashings and the cost to re-paper the roof with the correct membrane.

[Gus Potter]

4 hours ago, frslam said:

I live in the North West Highlands, it's strongly advisable to double nail all slate courses including eaves courses

Hope this helps to give you a bit of an insight, feel free to discuss. 

 

Your Highland location is relative as its very windy often and coupled with heavy rain.  But to start from not where you are! 

 

In the central belt and in the Scottish borders the general rule is if you were using Welsh, or Norwegian slate (these are a lovely green / blueish slate and very hard wearing, used in Edinburgh on high end houses)  say was to single nail every slate but cheek nail every third course. A cheek nail would go where the red dot is below. The head of the slate is kept square. The nail head is big enough to lock onto the side of the slate. All these slates are realitvely thin. A hard Welsh slate can be very durable but workable, the beds split easily in the quarry.

 

 

You would have a nail in the head of the slate. One inch down as below:

 

Now the beauty of this is that it make the roof easy to maintain. If you get a broken slate then you can turn the slates easily to fix the broken ones. 

 

Traditionally folk would get the Slater in every so often to check the roof and maintain, clear the valleys and check any drip type flashingsl for holes, often at low cost.

 

Now along came say the warranty providers. They are looking for say 10 years warranty. Now the cynical might say. See if we double nail every slate as above then the chances of a split slate falling out are slim as it very hard to spot a split slate from the ground.

 

Scotch slates are a different animal. They tend to vary in thickness a lot and are smaller. Because they are thick they are heavier so tend to lift less, parly due to their own self weight and the smaller size increases the density of the nailing. The nails are still one inch from the head so the bending force in the slate is less and this stops the slate from breaking at the nail point. 

 

Where this happens is down to the skill and knowledge passed down from traditionally father to son / apprentice. A skilled person will know that eaves, verges are vulnerable, but also around chimneys and the like. The wind in the highlands can be ferocious!

 

4 hours ago, frslam said:

He said that he wasn't going to grade the slates

 

He should have graded them. Cupa's at the very least in my view should be graded into two piles. Thick ones at the bottom, thin at the top. Usually I would grade into three piles. 

 

4 hours ago, frslam said:

I was unhappy with the membrane and to be honest with you

It's important to understand what the membrane is supposed to do. Traditionally there was no roof felt or membrane. There are many roofs in Scotland that just have slates on timber sarking. This worked traditionally as there was no insulation in the loft and any water that got in quicky dried out. I sometimes get asked this question and am acutely aware that if I'm insulating this kind of roof I need  be very careful, call it conservation design. 

 

In the (I think) 1930's they developed bituminous roofing felts, often called a type 1F today.  These were water and pretty much vapour proof. So to make that work they introduced eaves and ridge ventilation.

 

For all on BH.. Heads up! there was an invention of felt called ASTOS. Folk realised that you could use bitiminous felts for flat roofs but they burnt well. So they included asbestos. The clue is in the name. 

 

Your membrane is NOT intended to stop water ingress it's mainly there to stop wind driven snow, odd water mist and to let the roof breath. It's not like 1F felt and never has been intended to do so.

 

1 hour ago, frslam said:

looks like I'll have to take legal action

Your starting point is to really understand the mechanics behind this, how your roof was supposed to work and then why it's not. 

 

Legal action is the last resort. But before you even go there you need to check that the roofer has some assets you can go after. With a fair wind if he is not limited and has other assets, other than a marital home. Seek legal advice pronto before going down this route.. to freeze assets say , that is not free and if you do it maliciously then the builder will come after you!

 

Don't discount this. I had a Client that got trading standards involved in a case where the builder had been fradulent. If your roofer has stated that he has supplied, installed materials and billed you for it and it turns out that he never actually supplied the materials then that is fraud. Trading standards were supportive (the builder was already known to them as a chancer) so it might be worth calling them up to test the water. 

 

In summary though, you need to work out and check all your flashing and slate details and work out why the roof is failing in the geographic location, yes I know it's not finished. 

 

 

 

[Gus Potter]

To add an unfortunate bit.

 

 

Your verge closure seem incorrect. The vapour membrane should be under these. Traditionally these slates should be undertailed. 

 

Rather than write at length about this I've used AI and checked that what is says, I agree with. Copied below. I am of the view and have always done so when slating roofs in my last life as a builder that the verge slates should be tailed as well. In your Hhighland location we need to make use of every trick and technique. I wonder if your roofer can even beging to address some of the issues?

 

AI output:

 

The traditional method for "tailing" slates in a valley refers to a specific cutting and laying technique where the bottom edge, or

tail, of the cut slate is inverted to direct rainwater away from the vulnerable valley lining and back onto the main roof surface. This is a traditional craft skill that employs the principles of capillary action and surface tension to manage water flow effectively. 

 

 

The Mechanics and Importance of Traditional "Tailing"

 

Understanding how this intricate system works provides insight into the mastery of traditional slating. It's a method born out of necessity, predating the common availability and reliance on extensive lead flashing, and it continues to be valued in historic building conservation. 

 

• Capillary Action and Surface Tension: The technique relies on the natural properties of water. When a slate is cut, it exposes a sharp edge. Normally, water might cling to this edge or be drawn underneath the slate due to capillary action, potentially dripping onto the underlying valley lining (often lead) or the roof structure below.
• The Inverted Cut (Tailing): To counteract this, the slater takes the slate that is to be laid on the rake (the diagonal line of the valley) and essentially cuts its bottom edge as if it were the top edge (head) of a slate, or by flipping the slate upside down to make the cut. This results in the exposed, raw edge facing downwards, towards the eave, while the smoother, "dressed" (original) edge or a specifically angled cut faces up and into the valley.
• Water Shedding: This subtle inversion of the tail ensures that water running down the face of the slate forms a meniscus and trickles along the surface, shedding water back onto the top of the adjacent, lower slates and ultimately into the main flow channel of the valley, rather than dripping inward or compromising the integrity of the lead lining. 

•  

 

Why This Technique is Crucial

 

The 'tailing' technique is not just about aesthetics; it has substantial structural and protective benefits: 

 

• Protection of the Valley Lining: By actively shedding water away, it reduces the amount of direct impact and continuous moisture on the lead or metal valley gutter, which helps to extend the lifespan of the metal and prevents premature wear, corrosion, or pinholing.
• Frost Protection: A sharp, exposed edge of slate is more susceptible to frost damage and general maintenance-related damage. The 'tailing' method protects this vulnerable edge by tucking it or angling it in a less exposed manner.
• Preventing Infiltration: The primary goal is enhanced weather resistance. Traditional slate roofs are "water-shedding" systems, relying on gravity and precise overlapping rather than being a fully watertight membrane like some modern low-slope roofs. This meticulous detailing at the vulnerable valley intersection is essential for preventing water ingress into the building structure below. 

•  

 

Traditional Valley Construction

 

Traditionally, valleys were formed using skill and ingenuity before the widespread availability of modern materials. The slates in the valley would typically be laid over a robust wooden valley board, which was installed flush with the rafters. A metal lining, usually lead, was placed over the board. The slates from each intersecting roof slope are then cut and "tailed" to meet the valley line, creating a clean, weatherproof junction. 

 

Common traditional valley types also included:

 

• Double-cut valleys: Slates on both sides were cut to overlap a narrow strip of slates laid up the centre of the valley.
• Single-cut or half-swept valleys: Where one side (often the steeper pitch) was cut, and the other side's slates were swept across the intersection. 

•  

The 'tailing' technique is a testament to the high level of skill involved in historical slating, showcasing how traditional builders achieved durable, long-lasting results through an intimate understanding of materials and physics. 

 

In summary, 'tailing' in traditional slate valley construction is a superb example of how traditional crafts incorporate subtle yet vital techniques to manage water flow, protect materials, and ensure the overall longevity and weather-tightness of a heritage roof.

Edited 1 hour ago by Gus Potter

[frslam]

24 minutes ago, Gus Potter said:

He should have graded them. Cupa's at the very least in my view should be graded into two piles. Thick ones at the bottom, thin at the top. Usually I would grade into three piles. 

 

It's important to understand what the membrane is supposed to do. Traditionally there was no roof felt or membrane. There are many roofs in Scotland that just have slates on timber sarking. This worked traditionally as there was no insulation in the loft and any water that got in quicky dried out. I sometimes get asked this question and am acutely aware that if I'm insulating this kind of roof I need  be very careful, call it conservation design. 

 

Had the roofer come to work and done the roof when he agreed to, there would likely not have been a problem. On good days when you could get a lot done, I understood from others that the roofer may have been enjoying his favourite sporting pursuits.

 

The membrane issue ended up being a bigger issue than it should have been. The roof was letting in far too much water even 9 days after it was installed. The 9th day was the 14th December. Turns out the VELUX flashings aren't available until the middle of January 2026 so that's a long time to have the roof in that condition, there are 4  tall VELUX windows on the front elevation so it would have been limited as to how much slating could have been done before the flashings arrived.

 

The ungraded CUPA H3's were a problem. I own another house opposite the renovation which was slated in 2010 by a craftsman, when it was built. Pizzaro Paramo's (please excuse spelling) were used on that job and the difference between using ungraded and graded slates is quite stark.

[frslam]

4 hours ago, Nickfromwales said:

£30k is a lot of dosh for mediocre work and then having the house damaged too is just shocking.

I spoke to somebody today who asked me if there was a clash of personalities etc, was I treating him in a way that he had to leave the site? On the contrary. Trust was broken when he ruined 3 expensive windows, firstly agreeing to pay to fix them, then telling me that he wouldn't be doing that.

 

Another issue arose out of the machinery hire for a telehandler. We agreed that we'd hire one for up to 4 weeks. The telehandler arrived but the roofer did not. The machine sat and did nothing for a full week, the roofer didn't even turn up. The machine had to go back because it was pre-booked elsewhere. A 2nd telehandler from elsewhere appeared for a few days, the roofer still didn't turn up to use it at all, then it also went back to it's owner. The roofer then sends me a message to tell me that I am responsible for contacting the owners of the 2 telehandlers and paying them directly. I strongly disagreed, the telehandlers are on the roofers invoice, when the roof is complete, I pay for the telehandler. I understand how it works, not my first rodeo. A roofer can hire a machine for a month to use on a job but use the telehandler for 1 or 2 days out of that month. I understand the bill for the month is still payable when the job is complete. On this occasion however, when the roof work hadn't even started, the roofer wasn't even here to operate the 2 telehandlers, the 2 telehandlers arriving, sitting doing nothing before returning to the owners having not turned a wheel on site  but the roofer sending me a message to pay the bill directly to the owners to reduce his liability? Not a chance.

 

Now we get to the crux. Someone asking me today how I treated the roofer? My other half tells me she doesn't understand how I can keep my cool so well with the roofers behaviour. When I explained to the roofer that I wasn't paying extra for the telehandlers because the roofer wasn't even here, the roof job hadn't started and they were returned before the roof work started, his response to me (in writing) was "I really couldn't help that the weather was f%$&ed, my van was f%$&ed and the guy I work with was f%$&ed with the flu. Charming! Can hardly wait until that particular passage is read out in court