New Build Paving Slabs

[EmzehC]

Hello,

I am hoping to gain some expert opinions on the paving slabs which have been installed to the front and rear of my new build property.

As you will see from the images below, the slabs have some very dark markings present, which are also present on a number of other properties within the development. I have mentioned this to the developer and they have stated that in the groundworker's opinion its due to the fact that the cement still has water sitting in between. Is there any truth in this, or has this been caused by a manufacturing issue/the installation process?

https://photos.google.com/photo/AF1QipP ... QXpevp09zy
https://photos.google.com/photo/AF1QipN ... tZRR8YwCr0

Any thoughts or opinions are very welcome!

Thanks so much,
Emma.

[Tony McC]

Emma, your links are coming up as 404s - that's an error code for 'document not found'.

Have you removed the images?

[EmzehC]

Hi Tony,

Thank you for letting me know. The images were not removed, however, please try the new links below.

https://www.dropbox.com/s/pjfdg4faj7jrb ... 7.jpg?dl=0
https://www.dropbox.com/s/4vnsidj4wg0ot ... 9.jpg?dl=0

Thanks,
Emma.

[Tony McC]

Sorry it's taking me so long to respond. I am working 16 hr days at the moment and still can't keep up with everything that comes in via the website!

I *suspect* this is mostly a matter of wet flagstones drying out, and because of how they've been laid, they dry out at the edges first, and those 'circles' shrink as the drying progresses - is that what you're seeing?

It's not uncommon with these budget wet-cast flagstones laid on poor quality mortar or sand, but it's nothing to worry about, if truth be told.

[Tony McC]

....damn! Pressed the wrong button before I'd finished...

I was going on to say that we also see this type of marking when the flags have been laid onto rings of mortar rather than a full bed, and that *can* be a serious problem.

You can read more about that here: https://www.pavingexpert.com/layflag#ringbed

Does that help?

[EmzehC]

Hi Tony,

No problem at all.

This is all very helpful information, thank you - You mention that you suspect that this is mostly a matter of wet flagstones drying out. Do you think that is the case for the front and rear of the property? The markings appear to be slightly different (darker and wider spread) on the slabs at the rear of the property.

Do you think it is just a case of waiting for the drying process to complete?

Thank you in advance.

Emma.

[Tony McC]

I'm at a disadvantage because I can't see the paving for myself, but I would give the flags a short while, say 3-4 days of bone dry, warm weather, and see how it looks then,

If it is just moisture, then all the marking should disappear, whereas if it's reflectove staining, the marks, or most of them, should still be visible, but will appear much worse as soon as the surface is dampened again.

[EmzehC]

Hi Tony,

Both the front and rear slabs were laid around November 2020, so approximately 7/8 months ago. We have had some warm weather recently and there has not really been any improvement, so would you assume the staining will not resolve itself?

Best wishes,
Emma.

[Tony McC]

Probably. It's never easy to be certain with photies, but given this is not a recent installation, and the very bone dry weather we've been allegedly "enjoying", I'd lean towards it being a permanent stain.

Is the jointing a cement mortar or one of the resin compounds?