new roof problem

wazzoraybelle

Hope someone can help! I'm in the middle of building a sunroom/conservatory extension with a shallow pitched slate roof.We just finished slating yesterday and in the gale last night we lost a few slates. What's worrying me was the amount of noise the roof made it was quite a racket of slates slapping off each other. The pitch is very shallow <20 degrees and we live in a very exposed area. I saw an ad recently for a company that spray the underside of a slate roof with an adhesive foam which seals it (The sales pitch was for renovating old roofs). I've since lost the ad and am wondering if anyone knows who does this and how effective it might be at making the slates more stable. The roof is 3 metres deep and 10 metres long there is no way to make the pitch greater as the top is just below the windowsills of the main house. Thanks.

Mellor

Do you know what brand and type of slates were used exactly?

Concerns i'd have are:
At low pitchs, slates and tiles are secured with extra nails to prevent the slapping you mentioned. Has this been done?

In general the minimun pitch for slate roofs is 25 deg. This can vary up and down a few degrees depending on manufacturer.

In very exposed areas, were winds can be strong. The minimum pitch shouldn't be used. A higher pitch should be stuck to to keep the rooof stable.

The foam sounds like a bit of a gimmick, i've never actualy came accross is mind. But there should be no problems with a roof if done right, to right limits.

If your roof was so restricted that you were forced to go this low, then you shouldn't of used slates. Copper/Zinc would of been better. Even glas or a flat roof.

roofer

i would be quite worried as to why the slates were making such noise. slates dont usually slap around like that . is the top of the slate resting on the batton? slates are securly fixed and even in very strong winds it would be unusual to hear such a racket, even on a shallow pitch. i agree with mellor, low pitch roofs should be done in copper or zinc, you get longevity and piece of mind. as for the spray stuff, be carefull. i try not to criticize something i havent seen but if water is getting under your slates there is something wrong, i just wonder where the water goes once it hits the foam.

davidoco

http://www.renotherm.co.uk/ but you would have to remove the breather membrane from the underside which would lead to the risk of wind driven rain that got through the slate.

Slates

wazzoraybelle wrote: »

Hope someone can help! I'm in the middle of building a sunroom/conservatory extension with a shallow pitched slate roof.We just finished slating yesterday and in the gale last night we lost a few slates. What's worrying me was the amount of noise the roof made it was quite a racket of slates slapping off each other. The pitch is very shallow <20 degrees and we live in a very exposed area. I saw an ad recently for a company that spray the underside of a slate roof with an adhesive foam which seals it (The sales pitch was for renovating old roofs). I've since lost the ad and am wondering if anyone knows who does this and how effective it might be at making the slates more stable. The roof is 3 metres deep and 10 metres long there is no way to make the pitch greater as the top is just below the windowsills of the main house. Thanks.

What is the pitch of the roof?

What type and size of slate have you used?

What is the headlap of the slates?

What type of fixings have you used?

What is the rafter length?

What is the site exposure like?

How is the roof ventilated....Warm or cold?

What type of underlay was used ?

Is there any velux windows?

Give and answer to the above and we will sort you out ?

sydthebeat

Capco and tegral both do a propietory 15 deg slate AFAIK... did you use this type.
If not then your slate is inheritantly unsuitable for the roof, and you may get water ingress problems in the future.

Mellor

Not sure about Capco, your you're right on Tegral, their melbourne slate can go to 15 deg,
but the more common tru-tone and classic do not (25 deg & 22.5 deg respectively)

wazzoraybelle

Slates wrote: »

What is the pitch of the roof?

What type and size of slate have you used?

What is the headlap of the slates?

What type of fixings have you used?

What is the rafter length?

What is the site exposure like?

How is the roof ventilated....Warm or cold?

What type of underlay was used ?

Is there any velux windows?

Give and answer to the above and we will sort you out ?

Roof pitch 20 deg.
Slates are Rica 210 spanish slate 600X300.
If by headlap you mean cover then 5 inches.
Slates are nailed with 2 inch galv. nails with large heads.
Rafter length is 3 metres.
Sunroom faces south and is in a very exposed coastal location.There are 4 in. barges on the east and west edges.
cold ventilated with 'protect underlay'
2 velux 78x104cm.

Thanks for the replies. The roof is still there and the builder has replaced the lost slates. He also renailed some the loosened slates and it's quiet again. He seems to think the roof is fine and doesn't need any more stabilisation but I don't share his confidence.

Mellor

Do you have any product info on the tiles

JBCFord

wazzoraybelle

Any chance of building up your gables and putting an A roof or Hipped roof in place and putting in valley boards this would be my preference and keeping your velux on the south side you can install a lot more insulation with this type of roof

Your existing roof layout as you explained it I would personally would not have recommended or installed this type of roof in this location

What ware the factors involved on choosing to install this roofing method and type?

Regards jbcford

Mellor

I woudn't like the above. It means falling towards the house. If the junction has not been properly detailed it could fail.
Should of been right from the start

wazzoraybelle

Thanks for the replies, we've decided to take off the roof and install a zinc one.

sydthebeat

wazzoraybelle wrote: »

Thanks for the replies, we've decided to take off the roof and install a zinc one.

could you give us an indication in the difference in price between the two???

wazzoraybelle

I've no idea,tbh. I can only imagine that it will be more expensive.

rathlyon

Hi,

I am in the process of deciding between a zinc or a membrane flat roof. Would you mind telling me what contrcator you went with in the end for your zinc roof?

Regards

Tom