Which Cement

[annieigma]

Hi,
The end row of roof tiles needs cementing in etc. We used a bag of readymixed bricklaying cement from wicks, did the job. two weeks later, we went to put cladding on the timber under the tiles, just to make it look pretty, and when we hammered in the stainless white capped nails the cement broke up and some actually fell out. The nails are quite thin, so the hammering was gentle. what did we do wrong with the cement? should we have put chicken wire in the gap first?
Thanks,
Annie. And yes, this is the roof we put on two years ago!!

[Old_Geezer]

No expert but I reckon you can get away with hammering into mortar as I've done it, but to my mind cement or brick I'd expect to crack. I'm sure a builder will be along soon with a definitive answer though.

[The Builder]

I guess this is on the "verge", annie? (Gable end.)

"Pugging" with sand & cement is fine, but a better job is to roll up some galvanised wire netting and stuff that in there first. It also helps to hold the mortar while it goes off.

But, .......... this won't take any banging. It will break up for sure. Best to use rawlplugs and screws. Use a masonry drill but turn off the hammer action. You won't need it on recent mortar.

[TonyV]

Also use sharp sand rather than soft it will key in better

[jomifl]

Even plugging and screwing close (1 cm)to an edge can cause it to spall off.