Pointing old brick work?

Question

my brick work is about 75 years old and the mortar is a black

in colour ,how deep would you clean out and what mix would

you re-point with

Answer 1

Rake out to a min of 15mm wet the jointing down use a mortar mix in the ratio of 3 parts building sand to 1 part Portland cement adding a black mortar dye mix to the manufacturers instructions. The mix is not to be too wet or smudging will occur.

Answer 2

if you use a 4 1/2 in.  angle grinder and a 1/4 in. diamond blade to take out the old mortar , it will be almost an in. in depth...then add a little black coloring to some mortar mix and let it dry ...try different mixes till you match whats there...buy a tucking tool to tuck the joints with mud , dont use a trowel...

Answer 3

about an inch and a half should do it.if you can do it great because a brick layer will charge you a fortune

Answer 4

Alot of reading here for you

Good Luck

Answer 5

Take the old mortar out to just a bit deeper than the depth of the loose mortar. Use an angle grinder, dust mask and goggles. If you are likely to spray dust on passing public you need a pratective tent round it.

As to the mix, it depends on what is already there. Ask a local builder or surveyor. You need to depend on good quality local knowlege.

Answer 6

It would depend on the condition of the old mortar.

#1. Get a small angle grinder and put a diamond tuckpoint blade on it. Use gloves and googles. Cut into old mortar until it feels firm. You will get an idea of how deep to go then.

The horizontal joints are the easiest to grind out, the vertical or (head) joints you need to be a little more careful so you don't cut into the bricks.

Anyway, grind out the areas- now take a pump sprayer with plain water and flood the remaining dust/debris out of the joints. Now purchase your mortar mix and flat cement finishing trowel like a 4" x14", and a 1/4" tuckpointing tool.

Load up the concrete trowel (upside down) with mortar. Then hold the trowel right under the horizontal joint you need to fill.

Take the small 1/4" tuckpointing tool and slide the mortar off the concrete trowel right into the joint. You will get better as you get this procedure down. Try not to get messy with mortar- keep it off the face of the bricks.

Let mortar set up for about 1/2 hour then go back and tool the joints to get them smooth -still keep mortar off face of bricks.

For a better bond you can buy and additive to put into the mortar to help it stick better.

Good Luck

Answer 7

Most  of the answers to the question seem to me to be from people with no indepth knowledge of the subject.

The answer that I am about to give is based on researched carried out by the BRE (Building research establishment) a section of what was the  Department of the Environment)

In the answers I read almost all were advising that mortar should be 3 to 1 or 2 to 1 sand and cement. Mortar of this strength  would be a serious mistake and common among amateurs.

The mix specification should take account of the bricks and  mortar strengths. Cement rich  repointing mortar  shrinks away from the bricks that leaves fine cracks that encourage rain penetration.

The principle, repointing mortar should contain enough cement to be durable but must not be stronger than bricks, I repeat the mortar must not be stronger than the bricks.

If the bricks are old or weak or the mortar is old lime mortar (lime mortar contains no cement) Specify the weakest  practicable mix  consistent with strength e.g.

1:2:9 cement : lime : sand If frost is unlikely or protect for 7 days

1: 6 masonry cement : sand or 1 : 8 cement : sand plus  plasticisers If frost is likely.

If the bricks are sound and medium or high strength specify:

1 : 1 : 6 cement : lime : sand,  if frost is unlikely or protect for seven days.

1 : 4 or 5 masonry cement : sand  or 1 : 6 cement and sand plus plasticisers if frost is likely.

Specify that joints are raked out to depth  twice the thickness of the joint but not exceeding 35mm.

Specify the finish as  bucket handle joints, this give durability and weather tighness.

You will need to brush out and  wet the joints after raking out and just before pointing. This can be critical in hot weather it also helps reduce the suction of existing morttar. The idea is to slow down the setting action  this will prevent shrinkage.

In my personal experience it is best to use mortar that contains both lime and cement. A colourant can be added to get the desired colour this should not exceed  10% by weight of cement, if carbon black  it must not exceed 3%. Try to avoid repointing if frost is likely.

Black mortar is made  from slag crushed in a mill, its strength  depends on the quality of the slag. Sometime lime was added.

Answer 8

if the old black mortar is okay, leave it is. If it is a bit crumbly, then rake out the loose mortar about half an inch, and mix up a 3to1 sand and cement. Mix until you have a stiff mixture otherwise it will run all over the brickwork if it is to wet. Wet the joints with a brush and water, then using a pointing trowel press the cement into the joints. Clean off any surplus with the trowel then wipe around the joint with a damp cloth.

Answer 9

take out about three quarters of an inch of old loose mortar. Dampen down the brickwork with water. Replace using a mix of 2 parts sand (builders sand not sharp sand) to one part cement. you can buy  couloring to add to the mix but be sure you mix the same quantities every time or you will get mismatched colouring.

Answer 10

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