Hurrah, and Thrice Hurrah!

[Moo]

The ugly parapet above our leaky flat-roofed front bay came off a week ago, to be replaced with a proper watertight pitched roof.
This morning the Fixing Of The Slates was to take place.

But

Lovely Albanian Jim had to chop off some of the hideous (blue-painted) pebbledash before the Ceremony Of The Slates could begin, and -

There were the bricks, as crisp as the day they were rendered!!!!!!

So the little roof is on hold while Albanian Jim removes the rest of the horridness with meticulous care, and we are saved the extortionate cost of having the whole place re-rendered (if, that is, a lime chap could be found in the area).

The poor little house is really beginning to cheer up.

 

[Gareth Hughes]

Photos, please?

 

[Sonyaclegg]

I really love your posts. Always entertaining to read. I'm so pleased with your recent development. You are clearly delighted!

 

[andrew gayton]

is the pebble dash original or post build?

 

[Moo]

Oh, very post- build indeed!
The whole house has suffered from decades of bodge jobs, which is why it's in such a sorry state, and why we've been shelling out for builders to fill three ( or is it four?) skips with soil from inside and outside the rear extension so as to get the ground levels down to where they should be.
Which it why it was such a wonderful surprise to discover that the cementitious pebbledash had been thrown on in such a cavalier way. It took no time at all to strip the whole front ( mind you, it's a tiny house!).
I'll try to crank myself up to post a couple of before-and-after pictures, provided no one tuts about the windows which will have to stay until we've topped up the piggy bank a bit.

 

[andrew gayton]

a-ha. good work. hopefully the pointing survived! it would be good to see some pictures when you have the chance.

 

[JoceAndChris]

Pics!

 

[Moo]

Yes - even the pointing's ok. Well, most of it.
But I'm going to have a bit of a battle with the builders, who are dead keen to do a really good job for me, which in their book means raking it all out and doing a dead neat job with proper cement.
I'm going to have to plead poverty ( plenty of practice!) and wait until I can find someone who's willing to use lime.

 

[jocelyn plummer]

Great fun Moo, so glad the house is beginning to cheer up---- PICS please :wink:

 

[LadyArowana]

Such exciting developments. I know the old adage is "two wrongs don't make a right" but I guess the exception is the bodging of period properties. If they had done an excellent job of putting on the horrid pebbledash it would have caused dreadful damage to take it off. Doing a bad thing.... badly has turned out well!

 

[Moo]

Did I mention the pointing?

Just had a chat with the builder and have beaten him into submission thanks to what PPUK has taught me.
Unfortunately, in spite of following all the lime threads with rapt attention, I'm still a bit hazy when it comes down to the minutiae so I now need some answers:

1 What sort of lime?
2. Where to get it in SE22 ?
3. Can it be coloured to blend in with the original grimy pointing?
4. Not really essential, but I'd love to know whether there are any ElfnSafety issues involved with lime. The first time I mentioned using it, this was one of the reasons he gave for not using it.

And I really promise to get some pictures up before the day's out. Honest, guv.

 

[andrew gayton]

1 What sort of lime?
how old is the building?
2. Where to get it in SE22 ?
need to know the answer to no. 1 first
3. Can it be coloured to blend in with the original grimy pointing?
not really................ attempts to do so more often than not turn out a bit gaff
4. Not really essential, but I'd love to know whether there are any ElfnSafety issues involved with lime. The first time I mentioned using it, this was one of the reasons he gave for not using it.
as long as he wears gloves and wears a mask/goggles if mixing dry hydrate/slaking quicklime (unlikely to be doing the latter though), no more of an issue than using opc.

a friends daughter performed a 'snow angel' in a bag of my dry hydrate once and had to go to a and e due to blistering of her skin, so he best avoid doing that.

 

[AMc]

As an amateur I've done a bit of cement and a bit of lime (Hydraulic and Hydrate) "work". They are all nasty to deal with as powder so mask, gloves & googles are recommended (not that many builders will bother).

The last bag of Castle(?) NHL I bought came from Wickes and had recommended mixes for pointing, brickwork and rendering printed on the bag which seemed a sensible thing to do, but as andrew gayton says it depends on the house.

Your builder will have no problems making the transition just make sure they adhere to the correct mix. Where one builder followed his own thoughts he used way too much lime resulting in some failures.

AIUI this isn't the best time of year to be doing either cement or lime outside as a sharp frost can cause either to fail.

 

[andrew gayton]

hydraulic lime - don't get me started.

 

[plasticpigeon]

I can tell you my experience. Obviously Andrew doesn't agree but I thought NHL 3.5 was pretty standard for outside work on a brick house. It sets more quickly than putty based mortar. A 1:3 lime to sand mix is also what is conventionally used although some (for example Gerard Lynch http://www.brickmaster.co.uk/ who seems to be the messiah of traditional brickwork) swears more lime should be used as normally as 1:3 with quicklime is much more lime rich than 1:3 with hydrated or slaked lime!). In my experiments I wanted to get some grit in my mix as the original mortar had bits of sand up to around 5mm in it. However I have found that sharp sand from a yard has no fines in it at all so the mortar will come out grey/white. It is also difficult to use due to the sharp nature of the particles and the relatively large size of much of the aggregate. Plastering sand is generally sharp and fine which is good. This often is pretty clean too so doesn't give much colour. Building sand is soft and and is not really recommended by the lime experts as the greater surface area of the particles requires more lime, but it does give colour to the mortar. I ended up using 2 parts building sand to 1 part sharp sand initially, but now i am playing with 1 part sharp, one part plastering and one part building. I've done an unscientific test on my original mortar by taking out a chunk and crushing it up. It seems that the sand is not sharp (ie it feels soft when I rub it between my fingers) apart from the bits of grit, but even some of them are more like pebbles, so best practice was not always followed when a house was built originally. Also I think it is important not to leave the finish tooled but to either bash it with a brush or rub with a bag or something as this leaves the surface more porous. I hope the real experts will be along soon and hopefully won't tell me I've got it all wrong.

 

[andrew gayton]

as a general rule of thumb, the largest particle size of the aggregate should be as near to 1/3 the width of the joint that is to be bedded/pointed and equally graded down from that. so, a 10mm joint will take maximum particle size of 3mm, then down to 150 microns. however, in reality, this can cause some problems, more especially when repointing or bedding very porous bricks. to get the ratio of aggregate and lime correct, you take a jam jar, put an inch or two of aggregate in the bottom and slowly pour in water; once the aggregate is covered, this amount of water needed equates to the amount of lime required to adequately cover the aggregate. with regards to lime, the E.H etc mix of 1:3 is not correct - historic specs usually referred to ratios of aggregate and quicklime, so a 1:3 is actually more akin to a 1:11/2 / 1:2........ hence 'historic mortars tend to appear less sandy. There was a view put about that all historic limes were hydraulic following 'testing' but this testing did not take account of dirt/clay/etc in unwashed aggregates not ash within quicklime..... these 'additives' have a pozzolanic function that is far weaker than the current hydraulic limes. Also, the vast majority of limes used in the south east were from burnt chalk rather than limestone which produced a weker lime again. So, the widespread use of hydraulic limes does cause me concern in certain instances. Most builders like it because it is a chemical set rather than a slower carbonation - just like using opc infact.

 

[plasticpigeon]

OK NHL has a chemical set like cement, although much slower, but it is nowhere near as strong as cement, and still not a strong as the bricks either, so I'd have thought it fulfills the requirements of a mortar for a Victorian brick built house wouldn't it?

 

[andrew gayton]

your bricks look quite dense, so i am sure that you will be ok.

 

[andrew gayton]

I have just looked at your brickwork again; quite dense wirecut's, almost like a semi engineering brick? much denser than the gaults and certainly the reds in this area........... the acid test being that the brick is stronger than the mortar.

 

[Moo]

Gosh. Thanks for all that information. No wonder I didn't take in all those lime threads!

Andrew - the house is one of the bog-standard Victorian yellow brick three-bedroom terraces that were built in their tens of thousands all over London at the end of the C19th. From Booth's maps it's clear that they were intended for the very bottom end of the social scale (the 'deserving poor?).

SE22 is East Dulwich, which is just south of Peckham.