parapet coping

[2020c]

Undecided ether to use aluminium or concrete copings on parapet walls on a 3 sided extension.

The roof will be covered in EPDM up the parapet and over one skin of block. Dont know should i close the cavity or not or just leave opened if im using concrete copings or will i have to continue the EPDM over the second course of blocks then the concrete copings ontop of this. If so, will i need to install anything else for the cement to bond to the EPDM.

The aluminium is straight forward to install but its pricey.

 

[sxturbo]

The cavity needs closing,

Put the EPDM over the single skin, then close the cavity, need to use a dpc support, and then dpc on too of that.

If using coping stones they need to be mechanically fixed as well as being put on a bed of mortar.

There is also recommendation for a cavity tray to be installed.

Aluminium coping although more expensive is quicker to install and less time consuming

 

[2020c]

The cavity needs closing,

Put the EPDM over the single skin, then close the cavity, need to use a dpc support, and then dpc on too of that.

If using coping stones they need to be mechanically fixed as well as being put on a bed of mortar.

There is also recommendation for a cavity tray to be installed.

Aluminium coping although more expensive is quicker to install and less time consuming

Where does the mechanically fixings go if they are bedded in mortar!

I cant visualize what you mean by dpc support. Its it a case of closing the cavity with ply or insulated cavity closer, bed teh black dpc on this then bed the copings ontop of the dpc?

 

[sxturbo]

Bed of mortar is wrong wording,

Meant mortar pointing.

You can't just stick the stones on top of dpc with mortar they will last 5 minutes before becoming loose and you'll have major damp problems.

Dpc support https://www.roofingsuperstore.co.uk...HBRuZoB5NdxBh2tbe7bOmmkz933nMVrcaAmTOEALw_wcB

Another way to do it is just take the EPDM right over the top and put a drip edge on it.

I done that with fibre glass and it looked alright as it was grey it looked like the aluminium coping. Not sure what it be like with EPDM

 

[2020c]

Bed of mortar is wrong wording,

Meant mortar pointing.

You can't just stick the stones on top of dpc with mortar they will last 5 minutes before becoming loose and you'll have major damp problems.

Dpc support https://www.roofingsuperstore.co.uk...HBRuZoB5NdxBh2tbe7bOmmkz933nMVrcaAmTOEALw_wcB

Another way to do it is just take the EPDM right over the top and put a drip edge on it.

I done that with fibre glass and it looked alright as it was grey it looked like the aluminium coping. Not sure what it be like with EPDM

YEah i was thinking this would leak if installed as i said.

What is it im looking at on this pic of this product. I see the cavity closer and the dpc but how is the dpc bonded to the block or the EPDM to stop the copings from moving.

I had the drip edge in mind. Would it be similar with a batten around the top of the parapet on the outer face, run the epdm down over this and nail the edging onto the batten or no need for the batten and just secure it to the rendered blockwork.

 

[sxturbo]

YEah i was thinking this would leak if installed as i said.

What is it im looking at on this pic of this product. I see the cavity closer and the dpc but how is the dpc bonded to the block or the EPDM to stop the copings from moving.

I had the drip edge in mind. Would it be similar with a batten around the top of the parapet on the outer face, run the epdm down over this and nail the edging onto the batten or no need for the batten and just secure it to the rendered blockwork.

Yes to the last paragraph.

The link just goes to the cavity closer.

Mechanical fixing for coping stones.
https://www.roofingsuperstore.co.uk...act&utm_medium=affiliate&utm_campaign=1812968

The dpc I presume could be stuck down with a bed of mortar or grab adhesive.

The mechanical fixings would need to penetrate the dpc and EPDM so would need to be installed with sealant around the bolt and flange of the mechanical fixing.

Personally I would ditch the stones unless they are requires architecturally.

The aluminium or wrapping the EPDM over the top is overall, a much easier and simpler and cheaper way of achieving water tightness than the stones.

 

[2020c]

Yes to the last paragraph.

The link just goes to the cavity closer.

Mechanical fixing for coping stones.
https://www.roofingsuperstore.co.uk...act&utm_medium=affiliate&utm_campaign=1812968

The dpc I presume could be stuck down with a bed of mortar or grab adhesive.

The mechanical fixings would need to penetrate the dpc and EPDM so would need to be installed with sealant around the bolt and flange of the mechanical fixing.

Personally I would ditch the stones unless they are requires architecturally.

The aluminium or wrapping the EPDM over the top is overall, a much easier and simpler and cheaper way of achieving water tightness than the stones.

TY. Yes i would agree! If budget allows ill go with the aluminium but if not, the EPDM with the drip edge does seem a cost effective way of sealing it. I cant seem to find any info/pics or video on with the drip edge for a parapet. Have you pics of your own work with it?

 

[sxturbo]

Unfortunately I can't find the photos,

I did take some at some point, unfortunately I no longer live there so can't take any pics.

I did plan on rendering the walls so asked the roofers to put an inch batten round the edge to push the drip edge out a bit.