Pointing Mix

[DrWazzock]

I’m about to start pointing up my house walls again. They are limestone and sandstone. I’d guess they were originally built with lime mortar.
I’ve ordinary Portland cement, builders lime, soft sand and sharp sand. Generally I’ve used I think
1 cement
1 lime,
3 soft sand
1 sharp sand

The sharp sand seems to make it a bit too dark but more weather resistant.
I’ve read about proper lime mortar but it looks like a right clat. Would it be worth it?

 

[Lakesdigger]

Do not point sandstone with cement! Being a porous stone it needs to breathe so the pointing need to breathe as well. Trouble is as you say lime pointing is a right faff but I believe the only way to do it.
Not my area of expertise so can't tell you any more about it just I've worked at plenty of properties where sandstone buildings have been cement pointed and they've been re done with lime because of damp problems.

 

[Yale]

Hydraulic lime.

 

[Yale]

Guide to mixing natural hydraulic lime mortar

A comprehensive guide to mixing natural hydraulic lime mortar.

www.roundtowerlime.com

 

[br jones]

Do not point sandstone with cement! Being a porous stone it needs to breathe so the pointing need to breathe as well. Trouble is as you say lime pointing is a right faff but I believe the only way to do it.
Not my area of expertise so can't tell you any more about it just I've worked at plenty of properties where sandstone buildings have been cement pointed and they've been re done with lime because of damp problems.

you know that the sandstone will breathe all by its self ?so point it with what you feel comfortable with,personally my sandstone house is built with cement mortar ,no probs yet in 25 years

 

[Netherfield]

you know that the sandstone will breathe all by its self ?so point it with what you feel comfortable with,personally my sandstone house is built with cement mortar ,no probs yet in 25 years

This house built 1911 with sandstone, and cement pointing, re-pointed all round in 2002, no problems in all those years.

Famous for sandstone quarries in the area, all pointed with cement.

 

[Lincs Lass]

My friends brother does pointing but hes in Barcelona for the weekend ,could have asked him what mix he uses .

 

[Lakesdigger]

you know that the sandstone will breathe all by its self ?so point it with what you feel comfortable with,personally my sandstone house is built with cement mortar ,no probs yet in 25 years

You'd think that but not always the case from what I've seen. Depends on how the stone has been laid as well to a degree. Tbh best advice is that of someone local to the area who knows the stone as not all sandstone is the same and some may be ok pointed with cement and some may not. Also depends how much weather it will get due to location and direction it faces.

 

[suffolksmallholder]

I’m very lucky here in Suffolk to have lovely clean silver sand. Not too fine and not too coarse.
I’d avoid Leighton sand.
So my mix;
4:1:1
Sand: hydrated lime: white cement.
If you are doing lime mortar pointing and there’ limestone involved, I would use ‘eminent’ hydraulic lime at a 3:1 ratio.
Victorians used modern ‘cement’ at a 1:1 ratio with soft sand for pointing. This was into ‘moderate’ NHL 3.5 hydraulic lime masonry.
IMO I’d suggest a trial mix.
My go-to is the first listed.
Your choice.
Right now the weather is on your side.
Wet the work first and continue to keep it damp for at least fourteen days after.
SS

 

[C.J]

Beware that some NHL 3.5 will be whitened and some will be natural.

I use Secil NHL 5 for external use and limecrete floors.

Have a look at the Mike Wye website and videos .

 

[Forkdriver]

Is your house listed. If so you should match what's there already. Lime mortar is actually quite forgiving.

 

[suffolksmallholder]

Pictures of a wall built in 1859 and partially rebuilt in 2010. Both lime mortar, in my case ‘moderate’ NHL 3.5 at a ratio of 3:1.
The similarities in weather erosion to the mortar joints.
The modern version using a 5:1:1 mortar cement based mix with Suffolk sand, white cement and hydrated lime C2010. No weather erosion to both bricks or mortar. This is pleasing as a lot of local bricks suffer badly from erosion in the bottom twelve courses.
SS

 

[DrWazzock]

As I’m just filling in a few mouse and bee holes I think I’ll just use ordinary Portland. I’m not covering a big area at all so I don’t think it will significantly affect the walls ability to breathe. If I was doing it extensively I’d use lime mortar.

 

[renewablejohn]

Would not use anything else but lime mortar for pointing of any sort of stonework. Really easy to do with the right tools ie heavy duty electric drill, spiral mixer attachment, protective glasses (lime is nasty stuff in eyes) 15 ltr bucket, float trowel and tea bag.
Mix lime and sand dry with drill and spiral then add the correct amount of water it will look to be to dry but its not. Use float trowel to fold in round edges and base and remix with drill for a couple of minutes. Take tea bag and make a brew and enjoy the break for next 30 minutes. Come back and remix with drill for 5 minutes and hey presto the stiff mix before the brew suddenly turns into lovely mortar ideal for pointing.
Once you have mastered it you will never go back to using concrete as lime mortar is so forgiving.

 

[robs1]

Would not use anything else but lime mortar for pointing of any sort of stonework. Really easy to do with the right tools ie heavy duty electric drill, spiral mixer attachment, protective glasses (lime is nasty stuff in eyes) 15 ltr bucket, float trowel and tea bag.
Mix lime and sand dry with drill and spiral then add the correct amount of water it will look to be to dry but its not. Use float trowel to fold in round edges and base and remix with drill for a couple of minutes. Take tea bag and make a brew and enjoy the break for next 30 minutes. Come back and remix with drill for 5 minutes and hey presto the stiff mix before the brew suddenly turns into lovely mortar ideal for pointing.
Once you have mastered it you will never go back to using concrete as lime mortar is so forgiving.

Thanks for that we have a stone barn that needs some repointing, that info is really useful

 

[HatsOff]

Would not use anything else but lime mortar for pointing of any sort of stonework. Really easy to do with the right tools ie heavy duty electric drill, spiral mixer attachment, protective glasses (lime is nasty stuff in eyes) 15 ltr bucket, float trowel and tea bag.
Mix lime and sand dry with drill and spiral then add the correct amount of water it will look to be to dry but its not. Use float trowel to fold in round edges and base and remix with drill for a couple of minutes. Take tea bag and make a brew and enjoy the break for next 30 minutes. Come back and remix with drill for 5 minutes and hey presto the stiff mix before the brew suddenly turns into lovely mortar ideal for pointing.
Once you have mastered it you will never go back to using concrete as lime mortar is so forgiving.

Is that quicklime?

I've gone off NHL completely. I'd rather do a weak cement:lime mix instead of NHL now.

 

[zero]

We did a bit of patch pointing on a wall. I used some white cement to help it blend with the existing pointing. Sand from different merchants can result in a pointing colour change.

 

[renewablejohn]

Is that quicklime?

I've gone off NHL completely. I'd rather do a weak cement:lime mix instead of NHL now.

Normally use NHL 3.5 and its the brew which makes the difference.

 

[renewablejohn]

We did a bit of patch pointing on a wall. I used some white cement to help it blend with the existing pointing. Sand from different merchants can result in a pointing colour change.

Type of sand makes a big difference in particular the mix of graded sand particles. For pointing I prefer a coarse mix.