Patio Mortar Mixing!

Ta me anseo

Hi All!

I'm hoping to put a patio in the back garden next week and have a quick question about mortar.

The laying instructions for the type of paving I am putting down calls for a semi-dry mortar. It recommends a mix of 3 parts sand and 1 part cement. Is this 3-1 parts by volume? As in 3 shovels sand and 1 shovel cement in which case I would need maybe 15 bags of cement for a ton of sand? Or is it by weight, in which case I would need about 10 bags of cement for a ton of sand?

How much water would I likely need to add to make a semi-dry mix? I will be using a 'half bag' mixer which should take half a bag of cement and the appropriate amount of sand for each load.

Any hints would be appreciated!!

De_man

www.pavingexpert.com

ircoha

Ta me anseo wrote:

Hi All!

I'm hoping to put a patio in the back garden next week and have a quick question about mortar.

The laying instructions for the type of paving I am putting down calls for a semi-dry mortar. It recommends a mix of 3 parts sand and 1 part cement. Is this 3-1 parts by volume? As in 3 shovels sand and 1 shovel cement in which case I would need maybe 15 bags of cement for a ton of sand? Or is it by weight, in which case I would need about 10 bags of cement for a ton of sand?

How much water would I likely need to add to make a semi-dry mix? I will be using a 'half bag' mixer which should take half a bag of cement and the appropriate amount of sand for each load.

Any hints would be appreciated!!

OP: are u sure u need a 3 to 1 mix for the bedding; perhaps this refers to the mortar mix pbetween each individual paving block and not underneath.
However in the absence of the type of paving and the anticpated loading: eg prams or tanks, I wont say anymore. Just be sure as 15 ton of 3:1 mix is a lot of backache

Ta me anseo

The leaflet I have is for laying Tobermores Pietra Sandstone Flags. It says that I need a 35-50mm bed of 3:1 semi-dry sand and cement. It also says that I should use a 3:1 mix for pointing.

I intend to use an electric mixer for the mortar. I assume this will save me the backache!??!

ircoha

Ta me anseo wrote:

The leaflet I have is for laying Tobermores Pietra Sandstone Flags. It says that I need a 35-50mm bed of 3:1 semi-dry sand and cement. It also says that I should use a 3:1 mix for pointing.

I intend to use an electric mixer for the mortar. I assume this will save me the backache!??!

Am delighted to learn something new.

The mixer will save you some back ache but not all if u have 15 tons of material to move once to the mixer and then to the area where required.

The amount of water you will require is a function of how wet the sand is.

Elsewhere on this forum there are earlier comments re using an additive to the pointing mix to make it stick better to the edges

squire1

The bedding mix would depend on the traffic that will be on the patio as ircoha indicated. If you intend driving vehicles over it 3:1 would be appropriate. If however only foot traffic is intended, 10:1 would be fine. Somewhere in between the two might be the best compromise.

To get a semi dry mix you dont necessarily need to add water. The natural moisture in the sand will be enough. If the sand is particularly dry you could add a small amount of water but the drier it is, the easier it will be to work with. However, a very dry mix will take longer to go off so leave it for a couple of days before it gets heavy use.

Ta me anseo

Thanks for the hints people! I suppose I'll aim for a mix of about 5 or 6 to 1 then as it will be nothing other than foot traffic. I make that about 6 bags of cement per ton of sand.

ircoha, I am only paving a fairly small area, about 20 m2, so I shouldn't need much more than a couple of tons of sand in total I'd expect. Shouldn't be too much backache involved hopefully!

Ta me anseo

Just looking at pavingexpert.com and now I have another question!

I have ordered a ton of building sand to get me started. Should I have asked for grit sand instead? Will building sand + cement suffice for my purposes for use as a bedding material for my flags????

ircoha

Ta me anseo wrote:

Thanks for the hints people! I suppose I'll aim for a mix of about 5 or 6 to 1 then as it will be nothing other than foot traffic. I make that about 6 bags of cement per ton of sand.

ircoha, I am only paving a fairly small area, about 20 m2, so I shouldn't need much more than a couple of tons of sand in total I'd expect. Shouldn't be too much backache involved hopefully!

Nil me anseo in relation to this post: dont know where I got 15 ton: must be the cabernet: apologies:( .

As a matter of interest does the leaflet give a design load for using 3:1

Ta me anseo

Ha ha! Sounds like good stuff! I'll need to get me a bottle or two too!

No design load mentioned on the leaflet. I expect they may have simply covered themselves for the worst case.

De_man

Ta me anseo wrote:

Just looking at pavingexpert.com and now I have another question!

I have ordered a ton of building sand to get me started. Should I have asked for grit sand instead? Will building sand + cement suffice for my purposes for use as a bedding material for my flags????

building sand is fine i reckon 4-5 to 1 mix is perfect....for the pointing later use a little bit stronger...don't forget to get some dye for the pointing mix i recommend u use "marigold" dye...say a half a trowel per full mixer...let it mix fully!!! you'll be able to judge when it's the proper colour you might have to add a little more but its better to have the pointing a bit lighter in colour it'll blend in with the flags more easily...nothing worse than using plain mortar for the pointing


one more thing...if you think you may have probs getting the slope wrong...why not make up a timber frame say 4 X 1s fill the area with your mortar on a solid bed...screed it and drop the flags on top once it goes off abit...don't forget if your laying the flags adjacent to your home ensure the patio slopes away from your home and the top of the flag is at least 150mm below your DPC

Enjoy

Ta me anseo

Thanks De_man! I never thought of dye for the pointing. What colour would plain mortar work out as? The flags I am laying are pretty light, although I can see how a marigold dye would be quite attractive with the slight golden colour of the flags.

I'm fairly happy about the slope. The entire estate slopes in a direction across my garden and my patio will be at the back of the garden away from the house. I intend to leave a slight slope with the general incline of the land which will be towards the far right hand corner of the garden and unfortunately where the shed is! At least the shed is a good 6 inches off the ground! The worse thing I could do I believe would be to have it slope the other way so that any run off would effectively want to flow back under my patio.

De_man

which tobermore flag are you putting down?...the reason i ask - i took it for granted that it was sandstone colour thats why i said "use marigold dye for the pointing"...just as well i checked their website i see they've several products in that range


let us know what product from their range your going to use - we can recommend something then...that's if you're going to point the flags -

Ta me anseo

I'm laying the Pietra Sandstone Flags in Buff. They are a light golden colour.

ircoha

Ta me anseo wrote:

I'm laying the Pietra Sandstone Flags in Buff. They are a light golden colour.

Ta suil agaim nach bhfuil tu in an buff ag deanamh an obair seo:D

De_man

Ta me anseo wrote:

I'm laying the Pietra Sandstone Flags in Buff. They are a light golden colour.

marigold dye will be perfect...use a very small amount per mix say 1/4 - 1/2 trowel, add the dye slowly and let it mix fully before adding more

Ta me anseo

Go maith ircoha!

Nil se te enough pour moi na flags a layeail in an buff!!!!!

Loseaigh me mo brass monkeys otherwise!

Thanks De_man! I'll pick up some marigold dye tomorra!

Ta me anseo

Right everyone!

Finished laying the flags and it looks rather well I must say!

Only one thing I'm worried about... I used a 'semi-dry' mix for the bedding. As recommended on pavingexpert.com I did not add any water to the mix as the sand was already quite damp. I used about 5 to 1 sand to cement mix. This resulted in a crumbly mix that you could just about manage to carefully make a snowball out of but could never throw!!!! Hope that makes sense!

We got about half the patio laid on day one because of other problems.

On day two, we added a little water to the mix. My mate added a little too much on occasion and it did get quite wet and unfortunately seeped up the sides of one or two flags and there is a tiny bit of staining. Anyhoo, the wet mix was a dream to work with by comparison and i wish I had used it for the first half.

Now, the problem is this: The wet mix is already rock hard today. The dry mix (between the flags and around the sides of those on the edge) is still soft and crumbly and does not seem to have cured at all. I am very concerned that those particular flags could give awful trouble soon!

Have I done anything wrong? Can I rectify the problem? How?

I going outside to run the hose gently over the dry mix flags for a little while...

10-10-20

I seem to remember one of the websites saying that it could take the dry-mix up to 4 days/nights to 'go off'. Don't water it as you will risk diluting it down too much.

Ta me anseo

Do I need to hope and pray that it doesn't rain then? Even if I covered it and it rained, the rainwater would quickly seep underneath. Just fingers crossed I suppose!