Indian stone - Problem ?

[segovia]

Hi

Just had this paving laid a few weeks ago, these end pieces came a bit loose as I had some brick work underneath them re instated after the stone was laid (that was my fault) I lifted one today as you can see there is a void and a puddle under the stone. The grout is Rompox and it is very crumbly

Q Should there be a void and water under this ?

Q Should the Rompox be more solid and should it stop water seeping through?

https://plus.google.com/photos....sZik2AE

[Pablo]

The short answer is no there shouldn't be any voids and the Rompox shouldn't be crumbly. Your paving has been spot bedded on a plasticised wet mortar mix which is likely to cuase some very obvious efflorence staining in the outline of the voids. Your biggest problem though is the pointing Rompox easy is not a long lasting product especially if it's been brushed in like yours and not compacted and struck up. The paving is unlikely to get fixed but the pointing needs redone if it's not hardened well (if you can dig it out with a key then it's rubbish).

[segovia]

What does efflorence staining look like ? And how long does it take to appear.

So Rompox easy should definitely be compacted and struck up, I'll check the manufacturers guidance as I am sure this has just been brushed in.

Does other Rompox products just brush in, it could be that the contractor isn't aware of the requirement?


John

[Carberry]

What does efflorence staining look like ? And how long does it take to appear.

So Rompox easy should definitely be compacted and struck up, I'll check the manufacturers guidance as I am sure this has just been brushed in.

Does other Rompox products just brush in, it could be that the contractor isn't aware of the requirement?


John

efflorescence

All brush in products should be compacted and struck as far as I know.

[segovia]

This is taken from the Manufacturers guide - no mention of compacting

2 Open the cover of the bucket.
3-5 Immediately pour all the pavement fixing mortar carefully and evenly onto the surface and work it into the joints using a coarse broom (see diagram 5) or rubber squeegee
(see diagram 4), making sure it is in deep, hard and compact.
6 Then carefully sweep off the stone surface using a fine hair broom until all mortar residue has gone. Sweep diagonally to the joint. Swept off material cannot be re-used.
Subsequent treatment is not necessary. Any residue on the stone surface can still be swept off after 24 hours using a coarse broom.
7-9 The freshly jointed surface must be protected against rain for 12 - 24 hours. The protective cover must not be laid directly onto the surface, in order to ensure sufficient
air circulation (see diagram 9). Safe rain protection is afforded by the specially developed ROMEX® Paved Surface Protective Mats, that can be simply laid onto the surface
(see diagram . Please ask your trade supplier. During the initial period a very thin film of epoxy resin remains on the stone surface and intensifies the colour of the
stone and protects it from dirt. This film however, disappears from the surface in open weather and through abrasion in the coming months. In case of doubt please lay
a sample surface before carrying out the entire jointing work.

[mickg]

This is taken from the Manufacturers guide - no mention of compacting

2 Open the cover of the bucket.
3-5 Immediately pour all the pavement fixing mortar carefully and evenly onto the surface and work it into the joints using a coarse broom (see diagram 5) or rubber squeegee
(see diagram 4), making sure it is in deep, hard and compact.
6 Then carefully sweep off the stone surface using a fine hair broom until all mortar residue has gone. Sweep diagonally to the joint. Swept off material cannot be re-used.
Subsequent treatment is not necessary. Any residue on the stone surface can still be swept off after 24 hours using a coarse broom.
7-9 The freshly jointed surface must be protected against rain for 12 - 24 hours. The protective cover must not be laid directly onto the surface, in order to ensure sufficient
air circulation (see diagram 9). Safe rain protection is afforded by the specially developed ROMEX® Paved Surface Protective Mats, that can be simply laid onto the surface
(see diagram . Please ask your trade supplier. During the initial period a very thin film of epoxy resin remains on the stone surface and intensifies the colour of the
stone and protects it from dirt. This film however, disappears from the surface in open weather and through abrasion in the coming months. In case of doubt please lay
a sample surface before carrying out the entire jointing work.

I think the clue is in the last word of 3-5 ???

[segovia]

True, but it does say course broom OR squeegee - indicating there is an option - a course broom would not necessarily compact it.

The rest of it looks OK, and is hard to the touch however if you run your finger over it granules on the surface rub off - should this be a smooth finish or is that normal ?

[mickg]

that is normal if you have only brushed the product into the joints, using the brush with a forward and backward motion whilst pushing down you compact the jointing material into the joints

if you don't do this then its not fully compacted and if you lightly spray a hose over the area the jointing material would sink lower in to the joint but is easily rectified by adding more jointing material to these areas

if you had used either a brick jointer or finger trowel to compact the jointing material into the joints then the surface would be smoother and less chance of the granules being rubbed off with your finger

[segovia]

Many thanks, I'll see how it goes

Any views on the spot bed and the water underneath ?

John

[Carberry]

Many thanks, I'll see how it goes

Any views on the spot bed and the water underneath ?

John

As Pablo says, ideally it should be relaid but at the very least the pointing needs sorted.

[segovia]

I will obviously be relaying the one that has come up and not on spot sand and cement. Most of the others are solid to the tap with just the odd one sounding a bit hollow. What are the main objections to spotting mortar?

J

[Carberry]

Was about to type it all out but gaffer has already said it better than I can.

Why spot bedding is as useful as tits on a fish

[segovia]

Hi Thanks

The spot bedding in the example shown is not like my example, there is at least 90% mortar and it is 100% around the edges. When I watched them do this almost all of the ones I saw laid had 100% mix about 50mm thick. The base was also much more solid than what is shown. I had concrete flags there previously which had been laid on a solid bed of concrete. It will get laid back on a solid bed and the rest seem Ok up to now

J