Sandstone flag floor

[rocboni]

In my entrance hall I have a sandstone flag floor, albeit a bit random but it does look to be original. I scraped out the previous grout and what appeared to be caulk and I want to clean it, seal it and re point it. Can anyone recommend what to point it with? Some gaps are large and some extremely thin.

Also what to seal it with?

 

[Cubist]

I'm sorry to say it, but I think you're on a hiding to nothing. Much as I appreciate your desire to get, and keep, that hallways appearance clean and fresh the chance of success is, in my opinion, slight to none.

Sandstone is one of the more porous rocks and quickly absorbs moisture, The stains resulting from peoples journeys over it from outdoors will have penetrated to a surprising depth that no amount of cleaning - which relies on the dirt being 'lifted' out by some means - will achieve at all thoroughly. One of the very few techniques that could do this however is to use a surface grinder, such as those used to re-surface and polish concrete, but this relies on the gradual removal of the stones surface until the stains are eradicated. These machines rely on the use of water as a lubricant to facilitate friction heat dispersal and this, together with the vibration of the grinder, could seriously disrupt the floor and potentially destroy the sandstone pavers - sandstone can be surprisingly delicate. Another consideration for this approach must also be the thickness of the pavers themselves. Too thin and theres a prospect that they may crack and break or the grinder may cut straight through them to leave you with a pile of dust. In addition there is the possibility that the material in which the pavers were laid is too soft and may permit individual pavers to move in concert with the grinder and therefore defeating its purpose.

Frankly, I think your best option right now would be to use a wire brush and a little elbow grease on one of the worst stains to see if this makes any noticeable improvement before continuing over the remainder if it does. But, be ready to compromise, they'll likely never be pristine.

Before sealing the floor you would be wise to consider the nature of the materials directly below the pavers. If the floor was laid directly over earth or a much older flooring material then its probable that there is no DPM below it - safest assumption - and as a consequence groundwater damp may be rising through those pavers to escape to atmosphere via the hallway. Care should therefore be exercised to ensure that any sealant used does not close this avenue of escape as the damp will merely find an alternative route - perhaps into walls.

Typically with pavers the grout is applied in either a dry or wet powder form that is firmly brushed into the gaps. Wet grouts are usually associated only with glazed tiles or pavers as these will resist staining. A dry powder form would therefore be the best approach to use in this case. Once the dry grout has been brushed into all the gaps then it can be left to absorb moisture from the surrounding materials or encouraged with a few mistings of water from a spray bottle - but be careful not to use too much water as this could wash out the grout powder AND do not use a vacuum cleaner for at least a week.

Again, sorry for my negative outlook but I'm happier to be regarded as a 'negative killjoy' than a careless optimist.

 

[rocboni]

When we moved in it was much much worse than this, I cleaned it with a outdoor natural stone cleaner, keeping it wet and scrubbing with a deck brush and wire brush, we have been doing a whole hose refurbishment and that is the result after a year. We accept that it will never be clean as such but a sealer and point would make a difference. It's been there for 200 years so it's going no where

 

[a twig]

If it were me I’d use masking tape either side of each to avoid staining your freshly cleaned stone and regrout with NHL3.5 and plastering or kiln dried sand.

Depending on your enthusiasm for experimentation you could try brushing in dry grouting and then misting the joints with a sprayer afterwards, otherwise it’s hands and knees and finger trowels / old dining knives

No promises of success either way but just a suggestion!

 

[rocboni]

I'll give a small section a go, we know it will never be pristine, but we're not really looking for that...it's a lived in house. We just need the gaps filled sympathetically

 

[rocboni]

Well I've had a go and I am happy with the result, that's cleaned using an exterior patio cleaner, pointed with sharp sand and lime in the larger deeper joints to fill them up and kiln dry sand and lime on top.

I sealed it with some natural stone sealer Breath by floor seal. This is floors without a damp course.

Realistically it's going to need a clean once a year but it's no hardship really and the last dirt was from a year long renovation...

 

[Cubist]

Looking good, well done.

Theres a new member who has found an old sandstone fireplace hearth that's very grubby. I'll point him to this thread to crib some ideas.

Cheers,
Cubist

 

[rocboni]

The cleaner was the below...advise plenty ventilation

StoneCare4U Essential Natural Stone Cleaner (5 Litre) - Removes Dirt, Algae, Grime and More​

1. 

 

[aockenden]

Well I've had a go and I am happy with the result, that's cleaned using an exterior patio cleaner, pointed with sharp sand and lime in the larger deeper joints to fill them up and kiln dry sand and lime on top.

I sealed it with some natural stone sealer Breath by floor seal. This is floors without a damp course.

Realistically it's going to need a clean once a year but it's no hardship really and the last dirt was from a year long renovation...

View attachment 14733

Looks great. Nice work.