Quite possibly yes...and maybe not.
Lets look at why not.
Take a large nail to try and scratch the mortar.
If it is still hard and doesnt have the feel and consistancy of chaulk.
Nothing comes crumbling out.
No major cracks in the brickwork.
If the mortar joints are not all the way through.
It looks old the mortar hasn't got the same finish it once did.
...Why not just leave it, most likely it doesnt affect any structural concern.
Alternatively you could get someone to come out, give you a quote and advice which won't cost anything.
Or Maybe you just want to give the tired brickwork a facelift or new look.
If the mortar is crumbling,has a chaulk like consistancy(Scratch it with a nail) You should not be able
to scratch it out easliy at all.
Note:older houses using hydraulic lime mortar are different.
Have small to medium cracks that have deterioted over time.
You want a new look. You want to match mortar colour from an extension.
Heritage restoration like tuck pointing or older hydraulic lime mortar repairs.
Have had some foundation repairs/under pinning and need to repair cracks now everything has settled.
Then most likely...yes
Prices will vary a lot and can be quite expensive or reasonably priced. $50 for small repairs to $100 pm2 + for specialised work.
You may need heritage restorations like tuck pointing or just have 100 bricks to be re-pointed.
The above prices are estimates and to be used as a guideline only.
Not knowing your current circumstances like
*condition of mortar or tuckpointing
* paint removal
*scaffold needed...are a number of reasons.
My advice is this "Shop Around"
No big Ah-Ha there, that's pretty obvious.
Hear me out...
People usually give up after 2-3 quotes.
I suggest getting 5-10 and average out the prices.
This will also give you a decent idea about the industry (knowledge is power)
Don't just rely on me or other business you may have approached.
This is good practice in all areas. If you put in a little time and are prepared to be open to suggestions.
You just may get a really really good price.
E.G An older really experienced trades person(who's not really doing it for the money anymore) may take more time but you might win on price.
As an example when starting out doing smaller jobs from building houses on my own. I would ask the propective client if I could come out after work for a couple of hours.
Most often people were very accommodating I got the job they got a good price everyone was happy.
May not work in all situations just something to ponder on and listen for the opportunity.
Can be a costly project replacing crumbling,deteriorating old mortar in joints.
Working at height on scaffold everything has to go up and come down.
Extra safty precautions are needed.
If the Chimney is leaning over you will need it checked over by an engineer, if as mentioned above it comes under Heritage Laws you will need to restore it back to or as close to the original state.
While on the subject of heritage work Tuckpointing is an art form unto itself and there are specialised trades to do this type of work.So if it is something that you require my advice is dont get cheap here.
Though obviously do your homework,get plenty of estimates and be willing to adjust your circumstances if you are trying to get a good price.
If price is not an option get plenty of references and phone numbers of past clients. Don't settle for the privacy act crap(Yes it is a real law & I aknowledge that whole heartedly).
But if someone has done a really good job and have extremely happy clients. All a tradesperson has to do is call that past client.
Ask "Hi Joan ...it's Alan ...I have a prospective client that would like to speak to some of my happy customers would you do that for me please"
Crap past job=no
Happy customer= yes... It's that simple.
Ok a little rant sorry.
Stone walls have been around for ever.
In Australia over the last 40 years they are often used for gardens,landscaping,fences and decorative work.
Brickies Trowel, Hammer,Pointing trowel,Chisels (masons chisel, bolster,coal chisels) bucket,sponges
Depending on your conpetency you might find a make shift piece of steel in the shape of an S is appropriate to force mortar into cavities.
Clean out between stones to remove all loose rubble.
Clean with water to remove dust.
Mix only enough for half hour work( depending on your effeciency and weather)
Mix cement/brickies sand 4 to 1 to a plastersine consistancy not dry but not wet.
You can add an additive (Bondcrete) to make it stickier but please refer to directions as to type and amount when mixing.
This is easier to force into the cavity and will keep the stone clean.
When mortar is thumb print dry (meaning you can press your thumb into it with a little pressure)
Mist the joints with water (use a spray bottle if you wish) gently rub a sponge/paint brush against joints to your liking.
Cleaning stone is easier when mortar is dryer and will not smear stones.It is easier again the next day to scape dags off joints.
Tip if mortar doesnt match previous mortar you can make a slurry of the sand and cement you used(reasonably sticky with an additive).
Clean down and wet old mortar and paint the new mortar onto the old.
Then you shoulds have a new looking consistantly coloured stone wall.
In England and other climates with extreme temperature fluctuations they use a Hydraulic lime mortar mix for the elasticity/breathability
When winter sets in it doesnt freeze.It is also more sustainable.
See www.youtube link.com
Depending on the size of the wall, a house, large commercial building or a small section of 50 bricks.
You could use a trowel and dutch jointer(maybe called something else in other states) and finishing tools eg Raker,jointer,striking tool (for weather struck)or flush jointed.
If you are tackeling a large endeavour you may consider investing in a mortar bag(or make one yourself) or a mortar gun.
Same principles as before
Scrape out loose debris,remove dust with water, mix mortar (a little wetter than working with stone, consistancy of soft icecream)
Inject Mortar , let it dry till you can press your thumb/finger into it and finish accordingly.(test a small area first in not confident)
Clean up bricks when mortar is dryer and again the next day to scrape excess mortar of bricks. Use Hydrochloric acid in about a week. 1 part hydrochoric acid to 20 parts water. Add the acid to the water. Warning ! Proceed with caution follow all safety measures when dealing with any hazardous materials. Or use a qualified professional. Doing Repointing is not hard and in most cases you should be able to complete a small project yourself around the house or garden. If it is Tuck pointing well then that is another story altogether. But hey if you wish to tackle it and have a go. Who am I to say you can't... go forth and conquer. Most Brickies will give you basic advice and some tips to help. So don't be afraid to pick up the phone..