Wet Verge Mortar Mix Advice

[Cellophaneskies]

Hi all.

I’m redoing a wet verge on my garage roof. I’m all sorted and set, but I can’t work out what mix I need for the mortar for the wet verge. I find conflicting opinions online. I’ve finally narrowed down the mix I think in need - a combination of cement, building sand and shape sand and a plasticiser. I go to wickestoday to the material and I see the options of blue circle general purpose cement and blue Circle mastercrete, so I’m stumped all over again.

Does anyone have any advice on what I should be using for my mortar mix for the wet verge? Should I use general purpose concrete or mastercrete?

I’ve been tempted to just use ready mix mortar to take away these decisions but I’ve used it before and feel like it would dry with a rough texture - wet verges I usually see look smooth.

 

[Iwilldoit]

I think mastercrete has an additive to replace plasticiser. dont use readymix. In my opinion you do not need a plasticiser. I used 1-3 sand and cement with the sand made up from 1 normal and 2 sharp, but some sharp is rubbish with load of bigger than "sharp" in there.
I used a "stiff" mix otherwise it wants to slump and sprayed the area to be redone with water from a spray bottle first. Dont bother trying to smooth it off perfect straigh away and leave it to go off a little first.

 

[Cellophaneskies]

I think mastercrete has an additive to replace plasticiser. dont use readymix. In my opinion you do not need a plasticiser. I used 1-3 sand and cement with the sand made up from 1 normal and 2 sharp, but some sharp is rubbish with load of bigger than "sharp" in there.
I used a "stiff" mix otherwise it wants to slump and sprayed the area to be redone with water from a spray bottle first. Dont bother trying to smooth it off perfect straigh away and leave it to go off a little first.

Thanks for this. So you’re suggesting use standard blue circle general purpose cement -not mastercrete - and no plasticiser.

Ready mix seemed like a bad idea not without concrete (pardon the pun) advice, it was my last resort!

 

[Iwilldoit]

Either with or without mastercrete for the verge I dont think it matters but if you are going to have some cement left over to use on another job then for your next job you may "need" (need being - its better with ) the added plasticiser in the mastercrete one.
Have you google what plasticizer does. I remember old school builders adding a squirt of washing up liquid to the mix but I believe regs have taken over and prohibited the practice - hence proper plasticizer was bourn - or at least that is my DIY take on it anyway.

 

[Iwilldoit]

I think with ready mix like a lot of readymix stuff, its not as good as doing the mix yourself and also will work out more expensive.

 

[Cellophaneskies]

Thanks for this. So you’re suggesting use standard blue circle general purpose cement -not mastercrete - and no plasticiser.

Ready mix seemed like a bad idea not without concrete (pardon the pun) advice, it was my last resort!

Yes, I was going to buy some and add to the general purpose cement mix. Now unsure whether to skip that step and get mastercrete instead - I don’t think it’s much more expensive. Maybe you get less in the bag but I don’t think I’m going to need all of it regardless!

I think ready mix will work at the same cost for this one job, but I’ll likely have less left over in the end - but I’m not sure I’m going to need that.

 

[Dereekoo]

When I repointed my roof tiles and edge verge to extension that builder had made up with same mortar that he had used for brick laying (all of which subsequently cracked and was falling out) I used a 1-1-2 mix of OPC- sharp sand - sand but I wanted a slight textured finish which I achieved by trowelling up smooth and the wiping with a damp sponge before it had gone completely off as I think this help prevents/hides the cracks that develop in a strong mix. I didn't bother with a plasticiser as I wasn't to bothered about having a buttery mix that you go for when laying bricks

 

[Iwilldoit]

When I repointed my roof tiles and edge verge to extension that builder had made up with same mortar that he had used for brick laying (all of which subsequently cracked and was falling out) I used a 1-1-2 mix of OPC- sharp sand - sand but I wanted a slight textured finish which I achieved by trowelling up smooth and the wiping with a damp sponge before it had gone completely off as I think this help prevents/hides the cracks that develop in a strong mix. I didn't bother with a plasticiser as I wasn't to bothered about having a buttery mix that you go for when laying bricks

Same here - I replaced the rubbish job that a roofer had done which after 3 years the whole lot was cracking , flaking, crumbling, falling out.

 

[Harry Bloomfield]

When I did my verges, to help keep it tidy, I made up two lengths of angle iron, fixed together, flat faces in. That sat on the tiles, and against the wall. I started at the apex, just filling above the angle, letting it go off a little, then slid it down to do the next section, smoothing and tidying up behind. It worked out rather well.

 

[Iwilldoit]

When I did my verges, to help keep it tidy, I made up two lengths of angle iron, fixed together, flat faces in. That sat on the tiles, and against the wall. I started at the apex, just filling above the angle, letting it go off a little, then slid it down to do the next section, smoothing and tidying up behind. It worked out rather well.

Not sure what you are say there, did you not have any cement verge boards

 

[Harry Bloomfield]

Not sure what you are say there, did you not have any cement verge boards

There was just the tiles, slightly overhanging the brick of the wall. The cement verge was crumbling, so I redid it all. I made up an angle iron frame, as a guide - to get it even/ similar depth, and to hold the mortar in place, long enough for it to set up a little, before moving it on, to do another section.

 

[Dereekoo]

There was just the tiles, slightly overhanging the brick of the wall. The cement verge was crumbling, so I redid it all. I made up an angle iron frame, as a guide - to get it even/ similar depth, and to hold the mortar in place, long enough for it to set up a little, before moving it on, to do another section.

I'm still confused, if they were just tiles surely you would infill like this with just a trowel needed?

 

[Harry Bloomfield]

I'm still confused, if they were just tiles surely you would infill like this with just a trowel needed?

Like that, but slightly over hanging the brick wall, so it was originally flaunched, and that had broken up, and fallen away over the years. It needed redoing, and I'm hopeless at judging it by eye, so I made a guide frame/form up, from two lengths of angle iron.

My first idea for a form, was to fix timber battons, all the way along, but then I thought better of it, and made up the angle frame - which worked better than I'd imagined.

 

[Dereekoo]

If you mean adding mortar underneath the tiles in an upside down type of sloping flaunching, or in your case a rectangular blob of flaunch, can't say I have ever seen such a detail, neatest thing would be the flaunch to the underside of roof tiles before roofing felt was invented.

 

[Harry Bloomfield]

If you mean adding mortar underneath the tiles in an upside down type of sloping flaunching, or in your case a rectangular blob of flaunch, can't say I have ever seen such a detail, neatest thing would be the flaunch to the underside of roof tiles before roofing felt was invented.

I don't know the explanation of why it was originally flounched, but looking up, in my loft, I only saw the bare timber battens, and the underside of the tiles - which had very crumbly cement added to the underside. As that roof edge was very exposed, and the flouncing was breaking up, I thought it worthwhile ordering scaff., getting up there, and reflounching it.