Mortar mix over new concrete ???

[Boofhead]

Hi all, This is my very first attempt to concrete a path and i am hoping someone can give me a bit of advice, i am nearly finished the path, i've stuffed up a bit with the colouring of the concrete mix creating a few differant shades of a grey colour, i was only able to do a small section at a time because of my health.
The majority of it come out smooth but have a couple of my sections that are rough as, i have some stones protruding up a bit from the surface and looks like s..t, so i am wondering if i can go over the complete job with a colored mortar mix to cover any imperfections and get one good shade of grey all over the job, i've got a couple of mates that will give me a hand so it will make sure that its all done on the same day.
So here are my questions;
Is that Bondrete stuff any good ? if so, if i went over the job with it ,then put a coloured mortar mix straight on top of the concrete would it hold ? the path is an outside one which will have to take all weather conditions.
Is there any other ways you could think of, besides what i have said ?
I would really appreciate any good advise
Thanks

[Doughboy]

Boof

I am not sure about your success in this venture. I think that the thin coat of mortar would dry and crack, ending up looking like sheeite. Have you thought of gringing? Then perhaps you could paint with paving paint.

Other than these thoughts I am not sure but good luck with it all.

Pete

[Boofhead]

Boof

I am not sure about your success in this venture. I think that the thin coat of mortar would dry and crack, ending up looking like sheeite. Have you thought of gringing? Then perhaps you could paint with paving paint.

Other than these thoughts I am not sure but good luck with it all.

Pete

Thanks mate for the reply, I did think of use that pavementp paint it but not sure what gringing means.

[Clinton1]

I don't know much about concreting, but it may help others to know the thickness that you can accept for the new layer.... i.e. 5mm, 10mm, more.

Edit: gringing is a typo... grinding

[Boofhead]

A very thin layer, really just to cover the imperfections mate. i only know the old imperial measurements, 1/4 of an inch or so.

[johnc]

Do a mix of 2.5 sand to one of cement or buy premix render. To improve the bond you can mix cement and water together into a paint and brush that on first, a bit of bondcrete in the paint mix helps. 1/4" is a reasonable thickness, perhaps put up boards, or lift the form work if it is still there to form an edge to screed to and finish off with float and trowel. A barrow load should give you around 8' square, it goes a long way at that thickness.

The bond should prove servicable and unless it gets heavy impact should not lift or fracture. The greener the concrete sub base the better, so I'd get a wriggle on and get those mates around.

John

[journeyman Mick]

Boofhead,
if you want your topping to be any less than about 50mm (2" in the old money) you'll need to use a proprietry product specifically developed for thin topping coats. They're relatively expensive and are truly aweful to work as they have various epoxies or similar added to prevent them cracking. I can't reccomend any particular product as I've only used them a couple of times after which I decided I'd tell any prospective customers that I wouldn't do that stuff. Hilti shops should carry something suitable.

Mick (not genetically predisposed to work with concrete or any cemetitious products)

[Boofhead]

Thanks for your replies,
I am on a pension so i am trying to get the costs down as much as i can and if that bonding agent is difficult for a pro to work with, well i'de probably stuff it up for sure, so i think it might be the best shot if i use a grinder to smooth down the surface stones and if need be wack some liquid nails in any small imperfections i may create then use the paving paint, then job finished and time to crack a can

Thanks very much everyone, i really appreciate the advise.

[TEEJAY]

Thanks for your replies,
I am on a pension so i am trying to get the costs down as much as i can and if that bonding agent is difficult for a pro to work with, well i'de probably stuff it up for sure, so i think it might be the best shot if i use a grinder to smooth down the surface stones and if need be wack some liquid nails in any small imperfections i may create then use the paving paint, then job finished and time to crack a can

Thanks very much everyone, i really appreciate the advise.

My goodness - grinder, liquid nails then paint. :eek: Good luck.

Personally I recommend you read what johnc wrote above and apply it but it's your call and your path.

The only addition I would make to John's comments is the sand be medium river sand as this will give you a workable mix.

[johnc]

My goodness - grinder, liquid nails then paint. :eek: Good luck.

Personally I recommend you read what johnc wrote above and apply it but it's your call and your path.

The only addition I would make to John's comments is the sand be medium river sand as this will give you a workable mix.

Yep, But if you want to grind don't use liquid nails it will not last in that application. In anycase the sand cement mix is probably cheaper than the paint option anyway.

[Boofhead]

My goodness - grinder, liquid nails then paint. :eek: Good luck.

Personally I recommend you read what johnc wrote above and apply it but it's your call and your path.

The only addition I would make to John's comments is the sand be medium river sand as this will give you a workable mix.

Thanks for the good luck TEEJAY,
I have read everyone's reply and i am thankfull for all sugestions, is your recommodation based through your own personal experience doing a job similar to mine ?

[Boofhead]

Yep, But if you want to grind don't use liquid nails it will not last in that application. In anycase the sand cement mix is probably cheaper than the paint option anyway.

johnc - Thanks for the tip on the Liquid nails, i am glad to have mentioned it now, someone else told me its the ONLY stuff to use :confused::confused::confused:

Others have told me that Bondcrete is crap and won't hold the mortar mix:confused::confused::confused: these people are not pro's though so i am glad that i come here for clarification.
The complete area i am talking about would be about the size of a 10x10 ft room, i see that you mention to mix some bondcrete with the sand and cement, how much bondcrete are you recomending to mix in, because i don't know if you can get a smaller can than the one i seen at mitre 10 was about $50.
thanks everyone

[TEEJAY]

Thanks for the good luck TEEJAY,
I have read everyone's reply and i am thankfull for all sugestions, is your recommodation based through your own personal experience doing a job similar to mine ?

Hi Boofhead,

At risk of sounding like a smartaleck I will answer your question. But firstly let me say I don't like to sound as if I know all as many here know more from their own experience.

So,

My job is as a structural design engineer in a company that designs primarily concrete floors for shopping centres, high-rise buildings and the like - I have 13 years experience in this. We design and construct, so it isn't just theory. The company also has a remedial division that repairs large buildings, big dams, bridges etc. We use epoxies too in large commercial volumes.

But all that aside my recent experience at home has been building a pool and for this I have a concrete shell in place and they then put over it, around the perimeter, a bedding layer for the pavers to sit upon. This is really the domain of the tilers and pavers, not a design engineer, but I am keen to learn, so for this I share with you their recommendations.

The tilers applied a rich mix of water/cement/bondcrete to the top surface of the concrete pool edge, applied with a stiff scrubbing brush, this forms the bond between your render and the substrate (concrete path etc). They then made the render as johnc advised and applied this to the top of the pool edge and as such created a smooth level bed they assured me could only be removed with an aggressive jack-hammer. On top of the bed they glued the pavers and the job was complete.

In relation to epoxies - they are a difficult and extremely expensive product to use and not applicable to your situation.

Liquid nails also does not apply to your situation it is not durable and would not last and just make a mess of your path over time.

If you do a good job carefully using edgeboards for establishing your top level as johnc says you will for years appreciate a tinnie with mates on a job well done.

[Boofhead]

Thanks a lot TEEJAY,
No mate, " smartalic " doesn't fit in anywere into this thread at all, its good to get a few differant opinions then sort out the best approach to something that i had no idea about, as i like to do a good job and i needed good solid advise before i attempting the job, just like when you asked the tilers for reassurance if the base for the tiles would be strong as, if you don't ask questions you get no answers , believe me, i am so thankfull for everyones input.

The only thing now that i am a bit unsure of is how much bondcrete would i mix in with the sand and cement, probably 3/4 of borrow full should easily cover the whole area.
many thanks
Boofhead

[johnc]

Boof,

There are few experts here, so you do need to take the advice given in that light. I no longer work with concrete but for a number of years worked as a monumental mason, which involves some solid render or topping work which is in the ball park of what you are asking.

As you can see Teejay and myself are both in the same corner on this one.

I would only grind if you have some prominent points, and only then if they are going to rise above a rendered top coat.

If the concrete is very fresh you can get away without a bonding coat. The coat is simple, just raw cement and water with a bit of bondcrete thrown into the mix if you wish. It used to come in squeeze bottles similar to the aquadhere bottles only green. A small squeeze bottle would do but personally I'd just stick to the cement/water as you are on a tight budget.
The bonding coat when mixed should be a similar consistency to paint.

A local garden supplies should be able to sell you some sharp sand, usually river bed sand but read what Teejay said. Don't use packing sand or brickies sand as the clay content can be to high and will cause cracking as the job dries. (read what Teejay said about sand)

For the area you are doing one 40kg bag of cement and 3-4 bags of sand should be ample. If really trying to save the pennies don't put in colour, but if you do black oxide will be fine, but measure your mix by the bucket and oxide by the cup to make sure your colour is consistant if you have to do another batch. The mix as I have mention can be 2.5 sand to one of cement, that is the ratio I use but is not used by everyone.

To do the job set up the edge boards and get yourself a nice long board to use as a screed, it only needs to be slightly wider than the area you are screeding. Apply the cement paint with a stiff brush to the whole area then get ready to put on the top coat. Apply the mortar in small batches and trowel down roughly, then get someone on either end of the screed to level off. Tilting the screed backwards slightly will help force material into the hollows. The mortar mix should be the consistancy of a soft cow pat fresh from the cow, and it should not be difficult to screed. I would aim for a minimum thickness of 1/4" max of 1/2" in the hollows, to finish the edges remove the edge boards and run an edging tool around the edges. If no edging tool a single swipe down the edges with the wood float and a gentle 45 degree bevel will do the job.

If one of your friends has done some trowel work they should start off with a wood float to smooth the surface then finish off in wide sweeps for a smooth surface with a steel trowel. Obviously this is after the screeding has finished, if the work starts to dry to fast for you get a brush and flick water onto the area that is starting to go dry.

Please read this and then Teejays post they are consistant and if you have any questions just ask one of us will reply, we are both saying the same thing in different ways.

Goodluck, John.