Rescue brick and Portland-cement oven with fireproof screed?

[Stuizza]

Hello all, great friendly forum. Proper job!

Had some red house bricks kicking around the garden so went ahead and built a small domed oven. I must admit I didn't do my research before hand and I've just used a standard Portland cement-based mortar. The dome is very rough but it's holding up, and given I've no brick-laying experience I'm not disappointed. However, told my mates about it at work and they've all said I can look forward to an extra topping of mortar on my pizzas! So I've been wondering if there's a way to rescue my build and saw a heatproof screed made by Vitcas which you buy in rather expensive tubs and I was hoping to trowel a thick layer of this all around the dome inside hence stopping the unwanted mortar topping!

I wondered if anybody had rescued a similar build before using such a product? And if so how did it go? Did the screed adhere OK to the ceiling? Has the screed cracked itself?

Thank you for reading! And your help.

Stuart from Devon

[wotavidone]

What exactly was your mortar recipe?

[Stuizza]

Pretty strong, was a bit rushed come the end but I reckon 3-4 sand to 1 Portland.

Cheers

[wotavidone]

That's a pity. If you'd put a bit of hydrated lime in it, I'd have suggested you just leave it.

[Stuizza]

Yes, would have been a good call. I've seen the recipe floating around for refractory mortar. As you say hydrated lime with silica sand, and Portland maybe with some clay. Hindsight and all that. Well not to worry, I'll give this screed a go and report back!

Thanks for replies

[Toomulla]

If you have built it use it If it falls down which may happen in a short or long time fix it I am sure there plenty of cement \ house brick ovens that have lasted a lifetime particularly in domestic use , I don't believe any skim coat will help

[wotavidone]

Yes, I agree pretty much. I just didn't want to be the first to say it. I know a bloke who was in the materials technology game (holds a doctorate, no less) who called BS on the "must be refractory" thing and made his oven with ordinary Portland cement and sand. Still standing as far as I know.

[Stuizza]

OK, that's pretty positive news then. Thanks for the thoughts.

For info here is a link to what I was considering

https://shop.vitcas.com/hps-heatproof-screed.html

In writing seems just the ticket but I too have my doubts as to it sticking.

Sounds like I just need to get cooking and whatever will be will be.

Cheers all.

S