UKC

Having a bit of re-roofing done, and am curious about the way they have felted it. The roof is at a 16 degree slope, so not ideal, but this is the steepest it could be without really annoying next door. I'm concerned that it looks as if any water that gets below the tiles will pool and start to rot the battens, or find a way through- as you can see in the picture:

https://www.dropbox.com/s/imycigz8xsctxfy/2016-07-17%2009.33.48.jpg?dl=0

I know this is a work in progress and they've not put the plastic trays in yet, so they may do something to make it right, but should I be concerned? -Do I need to take it up with the boss?

In reply to markAut:

hard to say given the single photo and limited info.
take photos and let it play out, for now.
there are still plenty of options from this stage forward.
Saying all that the standard of building in the UK is shocking, I built McMansions in the US for 5 years and no idea how professional the firm i worked for was until I came back to the UK.

Document it all and best of luck to you.

If you do approach the boss man, the I'm just a punter could you explain it to me approach is sometimes a non confrontational way to get info out of them. Makes them feel good to have to explain stuff to you.

In reply to markAut:

Is this of any use?
http://www.roofapedia.com/FAQs.aspx

In reply to markAut:

I'd say that's not going to work. It needs a tray or stiffer UV-safe felt to run a fair way up the roof to get an angle that prevents the pool. There's no way to install it now the counter batten (on top of the rafter/truss) runs nearly to the fascia.

Pull the roofer on it. If no joy, point it out to your building control officer and let them explain it to the roofer.

Thanks everyone.
I'm going to have to have a word as there are a few things that don't quite make 'engineering' sense to me. Water flowing up hill for example. I'll quietly collar the chaps tomorrow. If they're there!

It's going to nag me if it doesn't look right.

In reply to markAut:

What tiles are they using?

I did a 16.5 degree roof in January ,and used Redlands Cambrians.

Marley/Eternit do a similar tile which is suitable for low pitch roofs.

In reply to markAut:
And .

That looks like the not so expensive Tyvek to me.

At the eaves,I'm always careful.

I doubt very much the plastic trays will work.i tried to find ones that would,but they only seem to be designed for steeper pitched roofs.

I always form an eaves tilt (with plywood) and use a '450 mm eaves protection strip' (bitumen) .it was the only product that would work.

And the whole area only works with the 25 mm counter battens .which you have used.

Low pitch roofs are not ideal.




Oh .and don't leave that Tyvek membrane hanging into the gutter.

In reply to andymac:

Yep, it's the Marley eternity one. From the batten spacing I have a feeling the top-lap distance is going to be a little small for building control's liking.

Anyway, we'll see. Always happy to learn if my understanding is wrong.

In reply to markAut:
I took the headlamp to the max .battens looked very close together.( approx 215mm from top of batten to top of next batten)
I was governed by the dry verge,interlocking units.



And ,while I remember ,I had to cut an an angle on the bottom of the counter battens,so that they would project down far enough to give a support / fixing for the bottom tile batten.
In summing up; the Melbourn and Cambrian may be suitable/designed for low pitch roofs ,but...the fact that they are only 300 mm long,makes the eaves detail very tricky .and awkward .on very low pitch roofs. If only they wer even 350 mm...

In reply to markAut:

If it's the Marley Melbourn ,they are identical to the Redlands Cambrian

In reply to markAut:

1; why has this roof got a counter batten.
2 . sarkin felt is a secondary line therefore no water should not pass line 1 , yes it may but how long will it hang around,
tray and eves felt now hard to fit

http://www.roofconsult.co.uk/articles/tiling/tips83.htm

In reply to Name Changed 34:

Thanks for this. Looks like I'm going to have a fun chat tomorrow. Just what i need!

In reply to Name Changed 34:

Counter battens are a standard detail in Scotland, but we always use sheathing ply or similar below the felt (or equivalent) I understand English detail doesn't,so the felt can sag slightly. The eaves detail itself should have a tilting fillet made up to avoid a trough from being created, usually from ply, as andymac said. The detail shown in the photo won't work.

To the OP:
What's under the low end of the spirit level?

In reply to Fraser:

That's a batten going across under the felt.

I suspect that there is a reasonably simple fix which will make it all work fine with minimal extra time lost. -probaby obvious to the boss, but not understood by the less experienced team doing the work. It's a shame that I need to supervise, but getting to a solution quickly is the important bit to save time, money and goodwill.

In reply to markAut:

Have a look at this,
http://www.manthorpe.co.uk/Building/Products/Roof-Ventilation/Felt-Support-...

In reply to markAut:

Yep, probably sensible to keep the goodwill and just raise a slight concern or query the 'finished' detail plan. Good luck.

In reply to Patrick G:



For low pitches ,where the eaves tilt is longer,they just aren't wide enough.

Ok on a 45 degree roof.not below 20 degrees

In reply to Fraser:

sorry! i did not know Mersyside had a home north of the border!
by the way What is the Minimum thickness for sarking board ?

'''The detail shown in the photo won't work.'''
lets define work
if part 1, fails water gets to the felt . the sagging in the felt at the eves will pond but just how much wet is coming in from a good roof, and for how long. further if the sagging felt fails the water go's to the soffit box or outer leaf. what then?
IF--- the tilling/slating is in good order with the right gauge for the pitch the felt should be snuff dry. Therefor it has no work to do, until the slating fails.

I have looked again at the photo I would say ask for a eves felt to be installed from the gutter back up say 500mm this could be a mineral the type used on built up flats roofs, you can talk till hell freezes over about if its fit for purpose but you have what you have and need a way out and a roof.

2. The farthest baton looks well back from the line, ? so nothing to fit first baton to.
3. Nails the rule is if you see any with any rust above the felt get the whole lot re fixed; its hard to see what we are looking at but the one nail hole is not jumping out as Galv

In reply to Name Changed 34:

The diagram in that link shows exactly the problem the OP has.

As a slight thread hijack while we have knowledgeable people reading. I had part of my roof replaced about 2 years back and have noticed that in high winds the felting flaps around a lot, any idea if this is likely to damage/impact the longevity of the felt?

In reply to gethin_allen:
yes it showing just that aas is a look at the two links to eves support

I don't know but what felt is it ? it may be a tail end that was not cut or it may be a end that has fallen as it was not fixed on a joint

In reply to Fraser:

On my daughters new house particularly the roof) we raised severel concerns which were totally ignored, and we ended up getting into major upheaval to get it sorted.

Given the same situation again I will get in there all gun blazing earlier. It would have been less stressful than trying to fix what becomes a bigger issue, so I think , if he op does not get a reasonable response , the OP should make it clear that he will stop work until it is resolved, rather than letting them proceed.

Thank you to everyone who has helped here, it is really appreciated. The climbing and ukc community is second to none with its depth of knowledge and willingness to help and advise on just about any subject imaginable.

In reply to Name Changed 34:

The product for the eaves you suggest is available.
It's called eaves protection strip.and is available of the shelf at Travis Perk

Rubberoid ,and other companies make it .comes in a roll 15m long ,and is bitumen based. It's quite thick and very durable.not to be confused with bitumen roofing felt.which is crap.

The flat roof underlay felt you suggest is not dissimilar ,but will still break down in the gutter.

In reply to Name Changed 34:

I'm not sure what felt was used, the flapping appears to be the movement of the felt that's sagging between the joists.
It's all bone dry so hopefully the felt won't need to do much but it does sound like I live in a tent when the wind picks up.

In reply to andymac:

http://www.manthorpe.co.uk/Building/Products/Roof-Ventilation/Felt-Support-...

This will work at 16 Deg, at 210mm and well fixed in place it will support the Tyvek ok and prevent ponding, I would not like to go much below 16 Deg mind, not ideal but then that is the drawback with low pitch roof's, wee sketch... https://www.flickr.com/photos/51033811@N08/28341920266/in/dateposted-public...

In reply to Name Changed 34:

I merely mentioned that counter battens being a standard detail in Scotland to highlight that their use isn't unusual. I've no idea where the OP's house is. His profile could be out of date or it could be a second house somewhere else - there are a number of possibilities.

I'm afraid I can't really follow much of your posts to be honest, you should try proof-reading them before posting to make it easier for the rest of us to understand them. I know what I'm talking about and stand by what I've said so far.

Sheathing thickness: I'd usually specify 12mm, you could maybe go to 9mm if desperate.

In reply to markAut:
We had a lean-to garage built last year with a 17 degree roof (slate). Architect specified rafters with OSB/Ply on top, counterbattened and either fibreglassed or hot-felted, then battens, then slates. Essentially wind will blow water up underneath the slates, so the roof underneath needs to be waterproof - the slates are pretty much cosmetic in terms of waterproofness. Think of it as a flat roof on an angle!
Like you, I have a 'kicker' (flat bit) at the bottom of the roof - what's the logic behind that? Why doesn't the slope simply continue down to the gutter?

In reply to Toerag:

He did What? ------------either fibreglassed or hot-felted, then battens, then slates!!!!!!!

Reminds me of one were tarmac has been specified He meant bitumen but after his 'I know what i said and what i want' he got tarmac ! that is Very difficult to water proof

In reply to Toerag:


It should, however at the final course of tiles immediately above the gutter, you have to compensate for there being no course of tiles below this on the bottom edge, as elsewhere on the roof. To do this, you'd usually introduce a tilting fillet of some kind. This maintains a fall on the felt, shedding any water which does get below the tiles/slates into the gutter, rather than ponding at the bottom of the roof, which is what will most likely happen in the OP's detail, as currently built.

Again, as andymac mentioned above, depending on the pitch of the roof, if a short tile is being used, you can sometimes struggle to achieve a sufficient fall in the construction. Generally speaking, the shallower the pitch, the longer the tile you'll need.

In reply to Fraser:

I know was trying to get a fuller idea of the job

>.......... I'm afraid I can't really follow much of your posts to be honest, you should try proof-reading them before posting to make it easier for the rest of us to understand them. I know what.>>>>>>>>>>>>

You mean post or any of your posts . If we are doing that !

..................I know what I'm talking about and stand by what I've said so far.>>>>>>>>>>>>

Im not and have not said you don't


I may be wrong but in the past no minimum thickness has been given, just that it should be used.

Sorry just read this
>>Generally speaking, the shallower the pitch, the longer the tile you'll need.>>
should we not say; the shallower the pitch, the longer the gauge/ head or lap you'll need.

In reply to gethin_allen:


It will wear it out much quicker than non-flapping felt.

In reply to gethin_allen:

on the good side you have a air flow

There was a 'felt' around in the 80 that was a plastic noisy as hell and did not breath it was black topside and gray on the underside

In reply to Name Changed 34:


What bit of that sounds wrong to you?

In reply to Name Changed 34:

What I meant was "I can't really follow much of [what is in] your posts." I was abbreviating it slightly.

I know.

I'd always use and specify it, but I believe that in England you don't *need* to have sarking, you could simply have slightly saggy Tyvek/similar, and eliminate the need for counter-battens. I think the minimum thickness might be one that would allow you to stand on it safely. I've not tried it but I think you can stand on Tvyek without any sarking.


We could, but for ease, I thought the phrase 'a longer tile' would be more easily understood by the layman.

In reply to markAut:

That pic looks a bit early to tell, but I would say that more woodwork to go on before anything else happens.

Ask the roofer.

In reply to Toerag:


This is what I fear.

In reply to all,
I know this is resurrecting an old thread, but would just like to thank everyone again for their help. I had at times, full and frank discussions with the roofers, but in the end we all saw each others points and found an amicable way to proceed and now have a good solution. Importantly building control were happy.

In reply to markAut:

What was the solution then?

In reply to Toerag:


All of it How the ehk are the battens going to fix without puncturing. slate waterproof why have the substrate.

In reply to Toerag:

Solution was as described above really, the batten along the eaves was replaced with a suitable but thinner one, which reduced the height of the gutter. Timbers were placed under the felt, along with suitable trays such that the bottom of the gutter was raised up. In combination the gradient of the felt was less that the 16 degrees pitch of the roof, but above zero degrees, so the opportunity for pooling has been eliminated.

Nothing technical, but just took a little time to understand the problem, think about the solution and not just use the first piece of timber to hand. Given the choice I wouldn't go with such a low gradient roof, then the problem goes away.