Corrugated garage roof to flat

[guvnor99]

Hi Everyone,

First post so please be kind

Seeking some advice to change my corrugated roof to a flat felt system. My garage is joined to the neighbours.

Currently the plan is to remove the roofing sheets, add a new lintel over the garage opening, add strengthing battons every 4ft to the roof. Deck out with 18mm exterior plywood and 3 layers of felt with a vapour barrier layer.

A couple of things im not sure about:

Where the flat roof meets the neighbours roofing corrugated sheet, how to go about finishing the edge to ensure there is a waterproof seal? Would it be best to felt over it or use some sort of sealent?

Currently the concrete lintel sits behind the solder bricks, I've uploaded images to show the bricks and existing lintel, would it be best to remove the bricks and replace them with the lintel or sit the lintel behind the bricks?

https://ibb.co/neb4cR
https://ibb.co/jYqmrm

On the edge of the roof sides, I was going to use 2x1 battons and finish the felt around it, would it be better to use an edging product?

Does anyone have a recommendation for roofing felt?

Any feedback would be much appreeciate. Thanks James.

 

[Notch7]

I would suggest using EPDM rather than roofing felt.

Roofing felt requires the training of a pro roofer to do properly.

So does EPDM, but it is more DIY friendly and the sites that sell it also have instruction pdfs and training videos.

I use https://www.rubber4roofs.co.uk

Is the corrugated roofing sheet asbestos cement based? If it is either get a company in or follow the correct procedure.

Joint to you neighbours roof is straightforward with EPDM. In general you would clean the existing (correctly if asbestos), prime, then use the EPDM joining tape or whatever method is recommended

 

[guvnor99]

Ive never come across EPDM but it looks very simple to use and apply in one go. Would I be correct that you only apply 1 x 1.5 Mm membrane vs 3mm of felt? Is this as hardwearing? Also could this be directly finished on the neighbours roof with the same adhesive?

As for the asbestos roofing, yes I'm aware of the precautions. Luckly no cutting would need to be done.
Just a double bag and seal to the local tip.

Any thoughts on the lintel?

 

[Tigercubrider]

I suppose that you have suggested to the neighbour's that you could both do the roof and split the costs?

 

[guvnor99]

Unfortunately the neighbours are tenants and the owners I dont ever see. Otherwise I would do.

I'm costing it up at about £750 all in atm

 

[geraldthehamster]

I second the comments about EPDM. I've done two large flat roofs with it, with no training at all, apart from reading, and watching Youtube videos. Easy to get good results. Main thing is to let the sheet relax flat before glueing it, and make sure the deck is dry. Make sure any seams are correctly bonded. It's much more hardwearing than felt, and has been proven to last much longer - correctly done installations have lasted for several decades so far. Unlike fibreglass you don't run the risk of leaving your boots stuck to the roof.

 

[guvnor99]

What your thoughts on corrugated bitumen sheeting?
Seems like a easier solution no need to deck out and easy to integrate into the existing structure with some additional supporting battons and no need for a new lintel etc.

 

[HERTS P&D]

I would be going for fibreglass, I done my garage roof approx. 40 sq metres and only learnt off a youtube video. It came out perfect.

Materials was £1200 including a large skip, new facia's all round and reboarding in 18mm ply.

Andy

 

[Notch7]

Ive never come across EPDM but it looks very simple to use and apply in one go. Would I be correct that you only apply 1 x 1.5 Mm membrane vs 3mm of felt? Is this as hardwearing? Also could this be directly finished on the neighbours roof with the same adhesive?

As for the asbestos roofing, yes I'm aware of the precautions. Luckly no cutting would need to be done.
Just a double bag and seal to the local tip.

Any thoughts on the lintel?

The 1.2mm would be fine. obviously you need to cover the garage roof with a deck first. OSB would be fine. Yes it would be as hardwearing. EPDM can stretch up to 300%, so although it isnt that thick and a bit soft on the surface, it wont get damaged that easily. It can get pierced by say the foot of an aly ladder if it was very sharp.

Im not sure I understand the issue with the lintel?

 

[guvnor99]

The 1.2mm would be fine. obviously you need to cover the garage roof with a deck first. OSB would be fine. Yes it would be as hardwearing. EPDM can stretch up to 300%, so although it isnt that thick and a bit soft on the surface, it wont get damaged that easily. It can get pierced by say the foot of an aly ladder if it was very sharp.

Im not sure I understand the issue with the lintel?

EPDM looks good but I'm edging towards fitting the bitumen corrugated roofing sheets, as it would be a much simpler task and alot cheaper. I wouldn't need to redo the lintel or deck out the roof, just fit extra supporting battons, thou decking out I wouldn't need the extra battons and maybe simpler??


I would think the fitting into the existing neighbours sheet would also be less of a problem. Has anyone had experience with these?

We had a quote for fitting a felt roof and they suggested a lintel to take the extra weight of decking it out.

As for osb vs ply there doesnt seem a great difference in cost.

 

[guvnor99]

The 1.2mm would be fine. obviously you need to cover the garage roof with a deck first. OSB would be fine. Yes it would be as hardwearing. EPDM can stretch up to 300%, so although it isnt that thick and a bit soft on the surface, it wont get damaged that easily. It can get pierced by say the foot of an aly ladder if it was very sharp.

Im not sure I understand the issue with the lintel?

This is a side view of the mantel, what concerns me is the bricks are attached to the mantel and have dropped and there seems to be a horizontal crack in the 'casted in situ' concrete mantel.

As the bricks had no support underneath which could be the reason they've dropped. (The bricks were installed before the garage door frame was fitted)