Rompox d1 vs gun applied external grout? - Best jointing choice for granite patio

[FBF]

Can anyone please offer advice on my choice of Rompox D1 for my silver and blue grey granite patio? I chose D1 as I have +/- 5mm joints at a 20mm depth and wanted something that would last well.

However, whilst talking to one Lithofin supplier yesterday about my intention to seal with Stain Stop then joint with D1, he said he wouldn’t use Rompox under any circumstances as it could possibly stain the granite – regardless of if it was sealed or not! His recommendation was to use an external grout applied with a gun like Webber Joint Pro, Ardex (not sure which one) or Bal (Superflex?). I don’t know if this will be more messy with a higher potential for staining unsealed granite than the Rompox?

I am aware that Rompox D1 will leave a resin residue that will wear away over the months, but has anyone heard of Rompox D1 staining unsealed granite (as mine will be now as I cannot seal till much later), and if so, what exactly happened and how was it rectified?

Is a flexible, waterproof grout a better option than the porous D1, particularly as many of my joints vary in size and some are narrower than 5mm? Is damp picture framing on the granite likely to be less with a grout than D1?

I would very much appreciate some guidance on this please as I need to make a decision PDQ! Thanks ;o)

[Tony McC]

Gun application is a real skill and it's awful easy to balls it up, resulting in mortar going bloody everywhere bar where you want it. It's also back-breaking, tedious and damned slow work.

D1, and other 2-part resin mortars *can* stain granite, and other porous substrates, but if the surface is absolutely soaked beforehand, truly saturated with water so that the stone is completely incapable of absorbing another single drop of moisture, then staining rarely, if ever, happens.

Finally, if your joints are only 5mm, then maybe an alternative, finer-grained 2-part resin mortar would be a better option.

[FBF]

Finally, if your joints are only 5mm, then maybe an alternative, finer-grained 2-part resin mortar would be a better option.

Thanks for your reply Tony.

Is the Gtfx VDW a finer grained 2-part epoxy than Rompox D1? I hadn't been made aware of such a difference when speaking with NCC or Cowley Stone. If not, what other product are you suggesting? I was told the Rompox D1 was OK for my 5mm joints at 20mm depth so I'm confused!

Re staining - we'll ensure the slabs are saturated thoroughly prior to applying the slurry, but besides the resin film, what does other staining actually look like if it does occur? Are there any photos of it on Paving Expert anywhere? I've only found reference to mortar staining which is why I didn't want to use it. I hadn't found any discussions or reviews of slurry 'staining' which is why I was so shocked to be told it could happen.

If slurry staining does occur, how can it be removed or lessened, or how long does it take to wear away? I know there are products that remove resin films (eg Lithofin Resin-Ex), but I'm guessing this wont work on an actual stain?

[lutonlagerlout]

vdw 815 is designed for thin joints
when we spread the slurry with a squeegee we are constantly misting it with a hose
once it is all in we start brushing with a brand new coconut brush diagonal to the joints
you do get odd low spots,so we reserve around 100ml to fill these as we go
no problems to date with this fantastic product
LLL

[FBF]

Hi LLL, Thanks for your response.

I was given this same advice by Cowley Stone for the Rompox: keeping wet and sweeping etc, so thanks for confirming that's what you do with the VDW.

From what I've read, experts such as yourself tend to prefer either the Romex or GFTK makes and stick to that choice. I admit I went with the Rompox because it was cheaper than the VDW (£330 vs >£1000), but I couldn't glean any disadvantage of this product over the VDW and the data sheet advises suitable for joints down to 3mm. It does recommend depth of 30mm but Cowleys advised our 20mm would be OK as it wouldn't be a high traffic area.

Have you ever used the Rompox D1 or is there any reason why you would recommend the VDW over the D1?

[Tony McC]

The 815 is specifcally designed for narrower joints. The Rompox D1 will work perfectly well in the wider narrow joints, if that makes sense, 4-5mm or wider, but some users feel that the coarser texture of a 'standard joint' product, such as D1 or even 850, is not as appealling in a narrow joint as, say 815.

[FBF]

Thanks for the explanation Tony. I hadn't realised there was a difference in the grain size from my research and I was of course going by what was said on the Romex data sheet.

I've now decided to enlist the services of a landscaper recommended by Cowley Stone who works with D1 all the time and I will be asking him to sort out the width / depth of joints as part of his works to ensure they are suitable for the D1.

My builders have never used a two part epoxy slurry before and I've had so many things go wrong on my project that I can't risk the jointing going the same way. Whilst this will be more expensive, at least I'll have a 5 year warranty on the joints and know that any possibility of staining will be handled with experience!