Garden Wall Project - help required

[spiidey]

r895neo: Thank you (as always); god knows where we'd be without your guidance (certainly not 3-4 weeks away from completion).

No need to haunch really if laying on a wet mix. its worth a little haunch but nothing major.

If we were going to do any haunching, where would you recommend we do it? At A, B, C or D on the pic below? Just C and D? The whole paving area falls/slopes downwards from A-D and from B-C i.e. from the top wall to the bottom wall.

You really want to lay your slabs near the steps on a wet mix or you risk them not bonding well. Using SBr or the bond bridge technique on paving expert will also help.

Thank you - will ensure we do this for the remainder of the slabs. How much in circumference/diameter around the steps should we be using a wet mix/sbr/bond bridge technique?

Picture framing can be avoided by making sure the slabs are a little damp and kept damp as laying proceeds. this stops them absorbing water and therefore cement. It more commonly a pointing problem though.

Thank you once again - the slabs we laid last week that ultimately became "picture framed" were laid bone dry (on a wet mix) so will ensure they're laid damp from now on.

A moist mix will be usable for 3ish hours depending on conditions.

Thank you.

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Are the following products ok for the pointing mix of 3:1 building sand / cement (laid semi-dry/moist)? Which is best - powder or liquid? Probably going to go with the brown as that's the instruction from the missus! If not, what product would be best / recommended?

http://www.jewson.co.uk/building-materials/chemicals/cement-colours/


What type/brand of plasticiser should be used for (a) bedding and (b) pointing?

 

[r896neo]

You only need haunching at a free edge so at the back i presume you are butted flags right up to the wall.

Continue laying on a wet mix its much better for a diyer to achieve a good solid bed. semi dry bedding has very little give so the bed needs to be very nearly perfect as the mortar will not flow under it as a wet mix does when tapped down.

Mortar colouriser doesnt work with paving. It will last a year maybe and then fade away to the normal grey. If you really need a coloured mix you need to use a pre-blended coloured product like parex easipoint or larsen GPM or try and achieve colour with your mix. i.e use white cement and a yellow or brown sand.

A preblended mortar would need to be applied with a mortar gun.

Any plasticiser will do. Use a normal one in a 5L tub not a super concentrated one. Its hard to get the dose right with a concentrate and adding too much plasticiser will cause mortar to shrink which for pointing can give problems

 

[spiidey]

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[spiidey]

We're laying the circle as shown in the pic below. I'm therefore going to have to lift (hopefully only some of) the rectangular flags that I'd laid before the missus decided she wanted a circle.

Two questions in this regard:-

1. For the 4 flags labelled 1, 2, 3 and 4, I'll lift these and hopefully get them up in one piece - they would then be used elsewhere. For the flags labelled 5, 6, 7 and 8, can I use a stihl saw to cut away what I need (i.e. along the green line) to allow me to fit the circle (i.e. cut the flags whilst they're mortared into the ground)? Or are there issues in doing this with a stihl saw (e.g. will the vibrations of the stihl saw weaken the bond of the mortar on the parts of the flag that remain in the ground?

2. The circle is going to leave c. 23cm of the flag on the top step (see blue line on pic). 2cm of this overhangs the step to get a lip on the step. Therefore 21cm will be mortared to the riser with 2cm overhanging. Is this too little a ratio i.e. with a 21:2 will the flag eventually rock/break/snap?

LINK TO ORIGINAL HQ IMAGE:- http://i62.tinypic.com/2db9rhv.jpg

 

[r896neo]

if its laid well with a bond bridge or mortar with sbr in it'll be fine.

Sawing in situ is not ideal but not a problem normally. It would be an issue near the step though.

Perhaps the best bet would be to relay the step ones by knocking them off the bedding and trying to leave the bedding intact. Then mix up some thin tile adhesive and stick it down with that. This will only leave you 3 mm higher which shouldnt be an issue and tile cement is probably the strongest bond

 

[spiidey]

if its laid well with a bond bridge or mortar with sbr in it'll be fine.

Sawing in situ is not ideal but not a problem normally. It would be an issue near the step though.

Perhaps the best bet would be to relay the step ones by knocking them off the bedding and trying to leave the bedding intact. Then mix up some thin tile adhesive and stick it down with that. This will only leave you 3 mm higher which shouldnt be an issue and tile cement is probably the strongest bond

Thanks. I'll have a go at sawing in situ and see how we get on. What do I need to watch out for that will tell me whether any of the sawing action is weakening the mortar bed?

If I have any issues I can always revert and knock them off the mortar bed and then relay with tile adhesive. Any particular brand you would recommend?

Finally, what about Q2 from my previous post?

 

[spiidey]

What type of sealant is suitable for this type of product?

Need the sealant to bring out the deep colours / wet look as the product we've had delivered is fairly washed out.

http://lsd.co.uk/bradstone-smooth-natural-sandstone-modac-spinning-circle

 

[r896neo]

Any tile adhesive suitable for exterior use will be fine. The 23cm flag is not an issue as long as it is firmly stuck. So rebedding it with tile cement might be a good idea.

As for sealers have a look through paving experts site there are some good recommendations on there.

A colour enhancing sealer by any of the main players should do. Aquamix colour ehancing sealer is often recommended by the sealers guru on the paving expert forum.

Paving needs to be bone dry before applying a sealer. A good one will be expensive, a few hundred probably. either use a good solvent based selaer or nothing. The water based ones are crap and are prone to problems

 

[spiidey]

Any tile adhesive suitable for exterior use will be fine. The 23cm flag is not an issue as long as it is firmly stuck. So rebedding it with tile cement might be a good idea.

Thanks, will re-bed with tile cement.

As for sealers have a look through paving experts site there are some good recommendations on there.

A colour enhancing sealer by any of the main players should do. Aquamix colour ehancing sealer is often recommended by the sealers guru on the paving expert forum.

Paving needs to be bone dry before applying a sealer. A good one will be expensive, a few hundred probably. either use a good solvent based selaer or nothing. The water based ones are crap and are prone to problems

Should the sealer be applied:-

1. Prior to laying/bedding;
2. Post laying/bedding but pre jointing;
3. Post laying/bedding/jointing?

Mortar colouriser doesnt work with paving. It will last a year maybe and then fade away to the normal grey. If you really need a coloured mix you need to use a pre-blended coloured product like parex easipoint or larsen GPM or try and achieve colour with your mix. i.e use white cement and a yellow or brown sand.

A preblended mortar would need to be applied with a mortar gun.

I'm finding it almost impossible to source a supplier that can provide the materials we need to do the pointing with a gun.

Is this product any good (i.e. will the colour hold beyond a year, and just how much of a risk of staining is there if done correctly)?

http://www.marshalls.co.uk/homeowners/view-weatherpoint-365-brush-in-patio-jointing

 

[spiidey]

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[r896neo]

Either you seal before laying as it can then be done in the dry in a garage etc.

Or seal about 2 months after laying. Some sealer require this wait to allow any efflouresence to breathe out.

marshalls 365 seems to get a good review by some of the contractors on paving expert and their word is good enough for me.

Its important to wet the surface before using it and follow the instructions. the resin in it can leave a sheen of sorts for a month or two in some circumstances i have heard but it disappears quite quickly.

The colour of 365 will hold as its pre blended.

 

[spiidey]

Back to the "haunching", r896neo when you say we need a little haunch, nothing major, what do you mean?

We're butting the slabs up against the wall marked A and B on the previous pic.

So do we only need to haunch at C and D? And only a "little"

Everything is being laid on a wet mix.

 

[r896neo]

just a little slope of mortar starting about halfway down the thickness of the flag and continuing out at 45 deg. It only needs to be the depth of the bedding material. no need to do any extra work.

Its just to stop the flag being kicked loose of its bed if you hit it from the free edge.

Like this if you imagine your flag was the grey kerb

 

[spiidey]

just a little slope of mortar starting about halfway down the thickness of the flag and continuing out at 45 deg. It only needs to be the depth of the bedding material. no need to do any extra work.

Its just to stop the flag being kicked loose of its bed if you hit it from the free edge.

Like this if you imagine your flag was the grey kerb

Thanks. So just to be clear, the "concrete" in the diagram above only needs to be mortar?

 

[r896neo]

yep just the same as the bedding mortar. firm it in well with a trowel if use a damp mix. if using a full wet mix just give it a smooth with the trowel