OMG- repointing dilemma?

[deano]

Right- I am embarking on a repointing job and want to do it PROPERLY BUT REALISTICALLY!

From research done so far I am confused as hell.

The house is circa 1900's terrace-end in North London. Soft red brick front facade which has recently been soda blasted to clean it up. Some pointing has been dislodged and there is evidence of various repair attempts over the years, mainly to lower parts (below bay window), ranging from hard cement based pointing to bay front and at the side of the bay a brick coloured stopper + thin ribbon line (I think) which seems to be an abandoned sample!

Owner wants complete removal and repointing so that everything matches.

My concerns are removing the existing without further damage to the worn brick edges (arrises?) and what mix to repoint with (lime/cement/ both), as well as joint profile selection.

As mentioned, I will take care to do a 'decent' job, but this is not a Grand Design's project, with unlimited time and budget.

I've done some extensive reading so far and am still unsure, so I'm after a general consensus from some of you who have travelled a similar path ;)

I'm aware this could rekindle a previous debate and hope to avoid that because whilst the 'jury is still out' these jobs will keep coming up :)

TIA deano

[Dean Heighington]

Just seen the Easy Raker from Mortar Sorta. Looks useful. Anyone used one?

[stuart noble]

The soft red bricks on the front of my house are very soft indeed and, because they're a uniform texture and colour, it looks bad if you lose the edge. I used a paint scraper to loosen the old mortar, mainly because it's a thin edge that you can tap sideways through the mortar. Certainly to start with I'd avoid the typical pointing chisel, which was slightly too fat for my mortar gaps

[Tabby]

Removing all mortar is not recommended, such bricks are often very soft and readily damaged by removing hard mortar. Just remove what comes out easily with a hand tool. Even a screwdriver is aggressive enough, no special tool is needed. You can make it all match pretty much by putting a wafer thin layer of the new mortar over any existing hard mortar.

Avoid ribbon style pointing, it increases water ingress which isnt a great idea with old bricks and wall types. Flush pointing was the standard at the time, weatherstruck is also used nowadays.

Lime mortar is best (3:1), it avoids brick damage and handles slight movement well . But lime is very slow to set. People have sometimes added 5% cement to get a little initial set. 1:1:6 is often used on these walls, but its a hard cement mortar, and damage in the future can result. Certainly avoid harder cement mixes.

With existing minor damage, don't get tempted to fill the gaps up with mortar. If the rain will run off, its better to leave it. Mortar filled brick damage is ugly, brick damage less so.

NT

[Dean Heighington]

Yeah, I know its gonna be some 'suck it and see work' and I want to make all efforts to avoid brick damage- they r quite worn already, but I also don't want to spend a month of Sundays at it! I'm guessing the stuff at the top will come out easily but there's a host of patching to deal with lower down- I think a grinder to centre cut the pointing here, is gonna be required!

The paint scraper is another good tool for me to consider as I have quite an array of these, as is a screwdriver and shave hook... Hacksaw blade?

Of course... Hadn't thought of that, theres prolly room due to weathering to allow this.

agreed, this looked like an attempt to square-up the worn bricks where it was done in that area.

Flush is what's used on surrounding houses (that haven't also been redone) but might look grubby when it fills the worn brick edges, as it will 'spread' so I was considering weatherstruck to define new lines, but this will obviously overpower the bricks- maybe a test patch and show the owner is in order here?!

So, use a little dust or not? I've read 1:1:6 a couple times in my research. Plasticiser in the mix not the gauging water too?

Do you mean likeIsaid above with the flush pointing 'spreading'? It would suggest a recessed joint to help define the brick edge but that comes with it's own problems of water ingress doesn't it!

Hmmnn, what-to-do...

Would still like opinions on this bit of kit, which I'd stretch to if it proved a timesaver whilst avoiding brick damage....

?v%3DPQZLI9Oqirs&ved=0CCAQtwIwAg&usg=AFQjCNHxpC5WHyvP8Lom6MGrrKEZc43FOQDeano

[Steve Firth]

I'm trying and struggling to find any element of DIY in your post. Did you mistake this group for alt.support.clueless.tradesmen?

[george [dicegeorge]]

If all the existing mortar is lime then you may be able to scrape it all out, if it's portland then it will be harder than the bricks and you would damage the bricks trying to remove it.

[g]

[Phil L]

If you rake it out by hand, it will take you about 4 days. Or a day and half by small angle grinder. Don't worry about damaging the bricks, they are usually unnoticed after repointing. I'd use a 3:1 sand cement mix, I've used this mix for pointing for the past

20 yrs and haven't had any problems at all. Use a decent ladder - one which is easy on the soles of the feet, IE not one with square rungs, get one with a flat rung if possible otherwise you'll have sore feet and legs after 2 days. Use goggles when you're using the grinder and watch out for various wires, I usually unclip them and add the cost of a few boxes of cable clips to the price - it makes it far easier for grinding out and also re-pointing.

I always wash the house down with a hosepipe after grinding, including all the brickwork, get all the dust out of the joints and off the brick faces especially. Start at the top and work downwards, and before you point anything, wet it first, a garden watering can is a must, If you've never pointed before, expect it to take you an hour per square metre.

A load of grit etc accumulates in guttering and gulleys, don't forget to clean these out at the end of the job.

[Dean Heighington]

Perhaps your time would be better spent doing something else.

No.

Why don't you go a find a comittee to run/join somewhere? I hear 'they' like clipboards.

[Dean Heighington]

Cheers for the input Phil, I'll be working off of a couple of towers so limited use of the ladder but no doubt there'll be some need. I respect your 20 years experience but am still unsure of using cement with no lime... If the wall micro-moves won't the brick faces pop? This is where there seems to be so much uncertainty about the subject. I think I'm gonna approach or with a centre score using a diamond Raker in the grinder and chip out the rest by hand for where it's stubborn.

[Phil L]

All houses are moving all the time, they're never still, believe me! Like I said, I've used this mix for 20 years without trouble.

It needs to be half an inch deep minimum (12.5mm)

[Dean Heighington]

Can I have a written guarantee? ;-)

Yes, with a nice flat back... Usually twice the width of the joint is what's in my head so there abouts eh?

I've done several patch works, but never a complete repoint so want to get it right. And, as you have probably guessed from my posts- there is so much contradicting data and advice from all points of the compass :)

[Phil L]

No but you can give one, safe in the knowledge that you won't get called back, trust me.

There's no set rule, I';ve seen brick joints an inch wide, they still get half an inch of pointing, which is more than enough.

Most of the advice about pointing seems to be for patch pointing - re-pointing an entire elevation or a full house is a completely different kettle of fish, spending too long on a square metre is unadvisable, whereas with patch pointing, you've usually got all day to do a metre or two, and the end result is immediately noticable (because it's new) as are any imperfections / scratches / damage etc - with a full repoint, it's all new, so nothing is noticable.

On this subject, measure your mixes and make each one exactly the same, use measures like small tubs, plantpots etc and shake each mix in a bag to get any lumps of sand out, don't mix enough to last all day because it's usually useless after a few hours, about 5kgs will last you a few hours and do a couple of metres and is easily mixed (dry) in a bag.

If you repoint in direct sunlight, the mortar often dries before it has set, and the following day it will be powdery, it will remain like this until it has enough moisture to allow the cement to cure, this often means wetting it down for a few days after, which will only take a few minutes with a hosepipe on spray, don't jet the water at it or it will wash out.

[Tabby]

This isnt true.

Indirect vent goggles. Too many people get injured using direct vent ones.

Modern houses dont move enough to cause noticeable external cracking. Old 1900 houses do, due to shallow foundations. Lime microcracks when movemnt happens, leaving the bricks unharmed and the wall intact, then it tends to self heal across the microcracks. Cement mortars result in split bricks in a line, ie much greater damage and expense.

There's no guarantee whether strong cement mortar will or wont be ok in 20 years. Many times it is. It certainly isnt when it eventually decays and rips the edges of the bricks off though, that takes more than 20yrs. 3:1 is a no-no for these properties, SPAB warns against its use.

Cement mortar mix should be discarded if not used in 40 minutes. A lime mortar batch can be used for days.

NT

[Tabby]

why would you spend ages on it? Soft mortar comes out easily, hard is just left.

I cant see why. Its certainly not advised. Its only making more work for yourself and damaging the wall.

too big

ok

too big

what for? It sounds like youre far overestimating the hardness of shot mortar. Bad mortar can be scraped out with a fingernail easily - not that I suggest doing it that way :)

you dont need room, just brush a little on with a paintbrush, its barely one grain of sand thick.

Flush is fine, better to match other houses in the area. There's no reason for it to spread, unless youre careless.

lime is a plasticiser. A little cement makes lime easier to work with, but do keep it minimal, it affects lime negatively. Other pozzolans are better.

No need to recess the joint, just dont also add mortar where there should be some brick but isnt, and give the exposed top of this mortar a very slight downslope.

If you think its needed youre way overestimating the hardness of bad mortar. Anything that would need that to remove should be left in place, just overcoat it to make it look the same.

NT

[stuart noble]

SF do carbide mortar rakes for an angle grinder. I imagine it might be difficult to see what you were doing though.

one fits a power drill

found the slower speed/less dust approach preferable on soft mortar. Just did a hole at each end of the brick and tapped the middle out with a screwdriver

[Dean Heighington]

The mortasorta had a footplate with notches, so you can tell where the cutter is- still a bit hit and miss though- not so bad on hard bricks as the cutter prefers the softer mortar to cut through.

From what's been posted so far, I was probably overestimating and most will come out with little persuasion... Only the tough 1:3 mix at the bottom will require some deft work with the grinder... That's likely the most problem area.

Limiting grinder use will also keep dust and noise to a minimum.

I also have to remove a couple of spalled bricks so the SC 125mm cutter will probably go on the shopping list.

[Tabby]

a screwdriver

/me adds you to the tradesman to avoid list

NT

[Phil L]

I'm not arguing with you, what I should have said is that when I repoint a house, any brick damage is unnoticable

I think you'll find this is due to sulphur attack of the old iron wall ties, and FWIW, nearly all the houses I have repointed have been Victorian

Never used it so I can't comment, but sand/cement IMV is the mortar to use, all the major pointing firms use it so that's good enough for me.

[stuart noble]

I have to say that, if I was pointing my house again, I'd give lime mortar serious consideration, but I can understand why contractors need something that goes off reliably in all but freezing conditions