No felt under the metal roof ?

[Lee Ridley]

My roofers fitted metal roof sheets ( steel box profile tiles) without the felt underlay. They had timber fitted onto the rafters and metal sheets screwed directly on to them. It looks nice, but I am concerned about the potential leaks and rain noise, too. They said that I don’t have to have the felt as I’ll have kingspan insulation with vapour  barrier.

The Kingspan insulation will be fitted between the rafters and underneath. Am I right to be concerned, or is it ok to fit it like this?? Can I do anything to improve it now? Appreciate any advice from the roofers with experience in metal roofs. 
Thank you.
 

[Lee Ridley]

1 minute ago, Lee Ridley said:

My roofers fitted metal roof sheets ( steel box profile tiles) without the felt underlay. They had timber fitted onto the rafters and metal sheets screwed directly on to them. It looks nice, but I am concerned about the potential leaks and rain noise, too. They said that I don’t have to have the felt as I’ll have kingspan insulation with vapour  barrier.

The Kingspan insulation will be fitted between the rafters and underneath. Am I right to be concerned, or is it ok to fit it like this?? Can I do anything to improve it now? Appreciate any advice from the roofers with experience in metal roofs. 
Thank you.
 

 

[Cpd]

Rushing out of the door but you MUST have felt under the roof if this is a habitable  / heated space. Others will be along shortly to advise. 

[smart51]

My garage is like that.  I use it as a workshop.  If I've been in there a while in cold weather, condensation forms on the roof.  I don't know the remedy but I know it's a problem.

[joe90]

I have metal roofing in my workshop and was worried about condensation so I used felt to catch it and it’s never been a problem but it’s only a Workshop. Personally I would have put felt in not to rely on the Kingspan to disperse any moisture.

Edited October 16, 2021 by joe90

[JOE187]

 From my experience a good quality breather membrane should have been fitted to rafters and taped at joints then the horizontal batterns on top.

Stopped internal condensation in unheated store shed of mine.

[Thedreamer]

What do you plans show? You should have a section plan which shows the breakdown of layers/materials in the roof, wall, floor etc.

 

We have a small metal room roof on our lean to and it has a breather membrane underneath to catch the condensation,

[Lee Ridley]

2 hours ago, Lee Ridley said:

Thanks. 
Anyone has any suggestions how to remedy the situation now? Taking off the sheets and starting again is not an option…
 

 

 

[joe90]

9 minutes ago, Thedreamer said:

What do you plans show? You should have a section plan which shows the breakdown of layers/materials in the roof, wall, floor etc.

Yes, what did your architect draw?, did your roofer follow the plans?.

[Thedreamer]

It would be useful to post an extract of your section plan. Here is mine.

 

 

You 

 

This is the first step to correct the problem. 

[JOE187]

I would suggest a sptay foam  carefully applied!

[nod]

I do quite a few jobs with these metal roofs 

I’ve never seen a membrane fitted Theres no chance of this kind of roof leaking 

The kingspan will sort out any chance of condensation Though they can be a bit noisy even when plaster-boarded 

[saveasteading]

 

Can  you tell us the product please? 

Whatever the shape, and this is pressed to look a bit like tiles, this is metal cladding. Therefore it ether needs to be sealed at every joint to be completely weathertight, or it needs to ventilate, and have another weather layer below it.

 

Even if sealed, you will have issues from condensation. 

 

My first impression therefore is that this is ok for a tractor  shed but not anything occupied or heated.

[Cpd]

4 hours ago, saveasteading said:

My first impression therefore is that this is ok for a tractor  shed but not anything occupied or heated.

 

8 hours ago, Cpd said:

MUST have felt under the roof if this is a habitable  / heated space

 

5 hours ago, nod said:

I do quite a few jobs with these metal roofs 

I’ve never seen a membrane fitted Theres no chance of this kind of roof leaking

@nod Is this on non domestic property? From what I can gather felt is pretty mandatory on domestic installations. 

[saveasteading]

1 hour ago, Cpd said:

There's no chance of this kind of roof leaking

At the ridge and eaves unless well fitted fillers and clever lapping used.

 

So that would be ok for an unheated shelter, and any condensation will run down the underside and then drip off the next indent. But not otherwise.

[joe90]

6 hours ago, saveasteading said:

My first impression therefore is that this is ok for a tractor  shed but not anything occupied or heated.

When I bought my metal roofing for my workshop I asked about their “anti condensation” panels, basically a fluffy inside face but it was explained that unless the sides are open, like a barn, the fluff would not be dried by the wind. So I used a membrane ?

 

8 hours ago, joe90 said:

Yes, what did your architect draw?, did your roofer follow the plans?.

If the roofer followed the drawings, ok, but if not ?‍♂️

[Iceverge]

Condensation will form on the underside of the roof and it will drip onto your kingspan and probably make its way through the roof onto your plasterboard. 

 

We have some old outbuildings and the underside of every single metal roof gets condensation. The only one that doesn’t drip has chicken wire strewn between the purlins to hold up some cheap roofing felt.

 

You’ll need to take the roof off and put up felt. Over the battens will work fine. 

 

On another note the fleece “non drip” roofing doesn’t work very welll here in Ireland.  For me roofing felt every time.

 

I wouldn’t put PIR in the roof either for a list of reasons as long as my arm. Use mineral wool batts or cellulose , airtight membrane, insulated service cavity and plasterboard. 

 

Edited October 16, 2021 by Iceverge