Re rendering small extension.

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FreeD

FreeD

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Got to re render this small extension.

I'm going to use Krend....but need advice on a couple of things...firstly the render has been taken up to the roof slates...there are gaps between the render and slates...water is getting in...how would I avoid this with re rendering?

Secondly the render has been taken down to the ground, i'm assuming there is a damp proof course and that bellcasts will need to be fixed on re rendering...what if blockwork is damaged below damproof course while hacking off?

thanks
 
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Yep they want it all hacked off and re rendered. Think the existing render is red building sand. It has blown in places.
 
why not hack out the blown bits, patch em in, top the whole lot with an acrylic thincoat? tidy that up dead quick and dead easy...

ground level -
put a stylsaw across the horizontal, 150 above ground, or just above dpc, whichever..
patch up the pointing, brick faces if need be, brick slips or full brick or just a 3:1 on an srbr slurry.. let it CURE then bitchumen paint... blackjack... synthaproof.... same sh't...

under the slates...
same as concrete or clay interlocking tiles, rosemary's, any roof verge...
if it aint dry verge (overhanging verge tiles/slates - got a little L shape? geddit?) then what it wants is hacking off without breaking the slates (tricky, would be easyier to remove em but seeing as theyre slate they'll be tricky to put back and stay put, dont go into it, its a long old lesson in roofing) so, tease off the render underneath, expose the ends of the battens (same as any tiled roof - every 250mm or so) and insert some cement verge board (like asbestos, its like a cement board bout 120 wide, 8mm thickish, comes in 2 or 3 metre lengths) UNDER the battens....
leave it flush with the edges of the slates (offers some support for the slates now see? stops em snapping off etc) and point it up with a good mix, stick some waterproofer in it...
do the point up in two hits... otherwise it'll slump, or get it in with a stiff mix.... normally you'd bed the verges on as you tile the roof and cut it off as it goes off, like bedding ridges, but you aint gonna be able to remove the slates without causing yourself a headache so i'd stiff mix it... its about supporting the slate edge whilst obtaining a drip and more importantly to the roofer - it helps you guage youre roof out..
guaging a roof is correctly is why you end up with the overhang in the first place....
wheres roofer2plasterer when you need him? send him a pm if youre stuck...
 
ive just read that back, dont continue reading unless you understand the previous sentence.. :rolleyes)
 
Thanks Chris. Think i'll get someone in to take a look at the slates, my main concern is water getting in where the slate meets the render, so putting a cement verge board in and pointing up will prevent water getting in? Should there be one in place? may it have been covered by the render?

As for ground level...thanks for the options, I take it I can butt any of these up-to the bell-cast no need to leave a gap?
 
rain fall downwards.. the verge is about support for the slates and guage, without it the slates are vulnerable...
the verge will protect the joint between verge board and render due to its overhang...
seeing as its already rendered to the ground, you dont need a bellcast, just a stylsaw and a steady hand, if you aint got a steady hand, pin a batten say 4" below where you want your cut line with masonary nails and run your stylsaw down the batten - nice straight line... hack off everything below it... the rain will drip off the render, make your cut more up than down - see? drip? lowest point?

or if youre gonna hack the lot off, then yes you need a bellcast, or just use a stop bead, but a stop bead hasnt got the lowest point on the outside edge... see?

below the bellcast is your dpc level, the reason the render needs to be above the dpc level is to stop ground moisture using the render as bridge to get past the dpc and cause damp problems... hence the blackjack to make it look half tidy once youve hacked off etc...

standard procedure all this mate...
 
Standard procedure m8 shame it wasn't done as standard in the first place. My thinking was that with the force of the wind the rain had been getting in under the slates where they meet the render (its cracked and blown there). But I don't know anything about roofing so...

As for the damp proof course and bridging, I usually set my bell-cast slightly above dpc. I would do the same on this job but obviously everything underneath is going to be damaged so if I paint this stuff on up-to the bell-cast will that cause a bridge?
 
looks like an original shape of extension that mate where next doors half has been taken down some time ago. probably has no dpc? Solid brick walls?
 
nah its cavity wall m8. i'm just going to remove render and see what i'm left with...I think marmorit do a plinth render...do you guys leave a gap between bellcast and the plinth, where damp proof course is or render up to the bellcast? I guess you could leave a gap by using a stop bead but is it necessary? will it look weird?

cheers
 
Is that a posh word for silicone?!

and one more question about this job the facia looks like a nightmare to remove...my gut feeling is to remove it, but if its solid in place would you bother or just render up to it?

ta
 
FreeD said:
Is that a posh word for silicone

and one more question about this job the facia looks like a nightmare to remove...my gut feeling is to remove it, but if its solid in place would you bother or just render up to it?

ta
Click to expand...
no silicone is silicone polysulphide is different it flexes more an used in expansion joints
 
FreeD said:
Is that a posh word for silicone?!

and one more question about this job the facia looks like a nightmare to remove...my gut feeling is to remove it, but if its solid in place would you bother or just render up to it?

ta
Click to expand...

leave it on but if its knackered and a b'stard to get off...
you can either try and tease if off from the underside without breaking any slate or best thing i find is a reciprocating saw with a progressor blade...
you can start in the middle of the timber a progressor blade as opposed to an edge and just cut either side of the rafters, removing the middle bit, between the two nails in the ends of the rafters...
what you end up with is youre taking the facia off in little bits without disturbing the slates...

or just get hold of some 250mm uPVC capping board and tack that over the top of the original to tidy it up a bit
 
Yea its not in bad way to be honest just a bit of a b*gger theres a 1 inch bit of render on the front above the window! Would you put a bellcast above the rear window?...looks like theres some kind of plastic tray above them at the moment.
 
thats a clip on drip bead mate, its halo profile, you can tell by the clip in angle along the top of the cill...
i'd just angle bead it three sides, keep it simple... run a gun line across drip bread / angle bead before you render it..
 
Ah ok i'll keep those in (or replace if damaged), think this extension looks better square...i'm thinking a stop bead will look better down the bottom as well, maybe 15mm then 10mm for the plinth is that bad practice or will it be ok? and whats a gun line? silicone?
 
gun line - line of low modulus neutral cure (high expansion, low acidity, sticks like sh't to a blanket)
 
lol thanks for that scientific definition, cheers for your advice Chris and all.
 
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