Sandstone wall advice

[Predatorx247]

I am looking to get some advice on a sandstone wall project.

I have been looking all over the net to find the answers i need but am failing, with everybody's answers clashing on forums etc.

The sandstone wall i intend to build will be as follows.
footings finished 100mm below ground level.
100mm solid concrete block on top of footings, laid flat - concrete block finished flush with ground.
100mm solid block laid on top of that, to retain raised lawn, with 3 courses of sandstone walling stone to face the block.
soldier course to finish.
total height of 335mm from ground level - lawn behind the wall fill finish approximately 25mm below top of soldier course.
I will haunch the back of the retaining block, line with a dpm to prevent penetration of water and infill with loose stone for lawn drainage.
on the lower garden level will be 60mm concrete paving blocks, finished about 10mm higher than the concrete block (purely so i can point from the paving to the wall) which will fall away from the sandstone wall.
I intend to seal the wall and patio with an appropriate sealer which i am yet to source.

My unanswered questions are:
-Is it ok to seal a sandstone wall
-Do i need to use a lime mortar
-If i need to use lime, is NHL 3.5 the correct type
-Can i add ordinary cement to the lime mortar
-Can i use just a cement based mortar
-What is the best mortar mix(sand type, cement type and ratio) to use given the spec above.
e.g. 8;3;2;1. building sand, sharp sand, lime, cement.
-Is it ok to add plasticiser or some form of winterproofer.
I want this wall to last as long as possible, hit the nail on the head in the first swing and not have to do it again in a few years.

I am under the understanding that lime is used as it is softer than sandstone and if it were to be put under stress, the mortar would fail rather than the walling stones. and it also helps with the evaporation of water?
if i have prevented water attacking the wall from behind as i mentioned above, and water will fall away front the wall at the front, and it is sealed, the only place i can see water getting the the wall is from the footings.

Sand grades and colour is another minor detail.
The paving is almost like a brindle block paving colour, not exact but near enough. and the walling is a natural buff colour.
i intend to point the paving with a geofix / pavefix type compound in a buff colour to compliment the wall. and the wall i intend to use a mortar mix for the wall which will have a red-ish colour.

An idea of the wall is below, but only 3 courses plus a soldier course high.
http://www.digbystone.com/browse-by-range/walling/

Any SOLID advice will be greatly appreciated.

 

[r896neo]

Your spec for the wall sounds fine. I would build it with a weak cement mortar. 6:1 or there abouts using a mix of building sand and plastering sand however I would be cautious about sealing it. Both the stone and a weak 6:1 mortar will be porous, if you had a coping ontop id say sealing would be ok but with a soldier course there's a lot more water siting and penetrating. You'd need specific advice from a sealer mftr.

Stay away from geofix, its trash. Marshalls weatherpoint, joint it, easyjoint or gtfk vdw range are a better bet.

 

[Predatorx247]

Thanks.

no mention of lime though? i hadn't planned to use it anyway but after reading many posts over the net with people recommending to use it that's what threw me.

whats wrong with geofix?

 

[r896neo]

I don't think you need lime that's why I didn't mention it. Repointing a stone building etc that may be built with lime and needs to breathe perhaps but on a garden wall being built from scratch I don't think its needed.

I lay a lot of paving and know many other contractors who have had terrible experiences with geofix. It is really a crap product.