Concrete Counter Experimenting

Andrea B.

Have spent time on web researching and now looking at doing few sq ft size exploratory trials, with view to considering for a kitchen.
Bottom line is that most of the sources for raw material for DIYers is US.
However I have come across a UK forum mentioning Hanson 40N readymix as a good solution.
I cannot find an Irish agent and have sent mails.
Has anyone had any experiences to share on a DIY front with an Irish source for the cement/concrete?

dathi

Andrea B. wrote: »

Have spent time on web researching and now looking at doing few sq ft size exploratory trials, with view to considering for a kitchen.
Bottom line is that most of the sources for raw material for DIYers is US.
However I have come across a UK forum mentioning Hanson 40N readymix as a good solution.
I cannot find an Irish agent and have sent mails.
Has anyone had any experiences to share on a DIY front with an Irish source for the cement/concrete?

http://www.irishcement.ie/wp-content/themes/irishcement/pdf/501_DL_flyer_1_V23.pdf

Andrea B.

Hi Daithi.
Thanks for link but my topic was unique to countertops.

dathi

Andrea B. wrote: »

Hi Daithi.
Thanks for link but my topic was unique to countertops.

if you had bothered to read the data sheet for hanson 40n concrete mix you would have seen it is just aggregate and cement . no waterproof agents no fibers nothing . concrete is concrete whether you cast it into a footpath or a counter top . how you seal it when its cast is another matter . and the 40n only refers to the final strength of the concrete and that is determined by the proportion of cement to aggregate to water.

Andrea B.

Easy on with the "if you had bothered".
It's a DIY forum ffs!
The Hanson 40N was mentioned on a UK forum as being a consistent mix suitable for my topic, namely countertops.
Was checking to see if other users had a more local offshelf proposal which (when mixed with correct proportion water) may give same result, bag for bag everytime.

jack of all

I read a book by this guy http://www.bookdepository.com/Concrete-Countertops-Fu-Tung-Cheng-Eric-Olsen/9781561586806?ref=grid-view when researching for a project years ago.

The contractor we used (who mostly did polished concrete floors) reckoned any good concrete mix could be used and polished (as Dathi is suggesting)- the trick was to adequately reinforce (chicken wire and 3mm steel rod around cutouts) sections and anticipate where shrinkage would be a problem. The material costs are lowish but skilled labour is important for a durable end result.

tabby aspreme

I don't know what part of the country you are in but if you contact ready mix suppliers and look for 40n mix with a max aggregate size of 10mm it should be OK, as you would only need a small amount you may have to collect it yourself as a dry mix and add the water on site yourself , or if they have a minimix truck they might deliver a 1m3 quantity of dry mix

jack of all

I would have thought that unless you're forming many 10's of sq . m of countertop (at maybe 50- 60mm thick?) readymix is a waste of time- you need time to place and finish the small volumes of concrete required, even in a large kitchen the counters probably could be formed from 3- 4 barrows of concrete batched and mixed as required?

Andrea B.

Thx folks. I would be OK with 20 bags ready-mix for my volume.
To start looking at some low volume 1bag trials.
Have some useful info from all.Thanks

tabby aspreme

jack of all wrote: »

I would have thought that unless you're forming many 10's of sq . m of countertop (at maybe 50- 60mm thick?) readymix is a waste of time- you need time to place and finish the small volumes of concrete required, even in a large kitchen the counters probably could be formed from 3- 4 barrows of concrete batched and mixed as required?

1m3 of 10mm drymix dropped on site and mixed as needed would be very convenient and probably no more expensive than buying everything in small bags and trying to work out ratios etc, any surplus could be put to other use

Safehands

dathi wrote: »

if you had bothered to read the data sheet for hanson 40n concrete mix you would have seen it is just aggregate and cement . no waterproof agents no fibers nothing . concrete is concrete whether you cast it into a footpath or a counter top . how you seal it when its cast is another matter . and the 40n only refers to the final strength of the concrete and that is determined by the proportion of cement to aggregate to water.

Wow Dathi, poor Andrea. Where you got that statement from I don't know, but Andrea would be best advised to ignore it.
Andrea, loads of experimentation on this one. There are so many options which will make a huge difference. Start off by mixing your own concrete. Test various admixtures and various different sands / aggregates, reinforcing, colours and stains. Test the different types of cement too and the sealers.
Concrete is not just concrete. There is a whole world of different mixes to be played with, so have fun.

Andrea B.

Well after some experimenting, a fair bit of reading and a good few hours, I dived in and formed the most challenging (sink) section first. See image below and close up. Couldn't be more pleased with result and smooth finish.
Rest of kitchen worktop should flow more smoothly :-) Thanks for pointers and encouragement.
Second image shows the detail in front of sink.

pic host[/url
image hosting services

jimbev

Well done great result, how will you butt the next counter top up

Andrea B.

Thanks. Planning on a dark grout and flush polishing.

Calahonda52

A B.: that is quite a result!
Fair play: when I need the next batch of architectural panels I know where to go.
Just wonder how you did it: i.e. did you cast it upside down and then turn it over?

Also what mix/rebar/additives etc?
What thickness is it?

Andrea B.

Thanks :-) Was kind of fishing for compliments. Need a lift due to some circumstances of late.

Anyhow, to share some more, an image chronology below.
40mm thick. I might have risked a bit less, but wanted meat for sink section.
Cast upside down.
1:1:3 portland:white chips:coarse sand
Rebar with an emphasis on sink area.
I added fibre additives I got off EbayUK, but everything else within a 5 mile region.
Kept it insulated from frost while curing and gave generous radii to inside corners for sink so as not to create a crack propagation point.
Will be sealing with Tung Oil, but only when I have the next 6 linear metres, incl breakfast bar complete.


Some trials


The form and rebar


After pour


Form removed


Flipped and ready for polishing


Polished


Frame to avoid stress on sink region while carrying in


I won't post an image of my wife, who gave me encouragement, coffee and motivation, has great patience...........and is smiling now :-)

jimbev

What did you use to get the colour of the sample on the left and do you have an idea of what the work tops would of cost ready made and what sort of weight are the tops

Andrea B.

No colour additives for that, just red sand and pebbles and some green glass.
About 60Kg.
Granite or quartz starting about e400 a linear metre.

jimbev

The red sand looks great made the mistake of showing my wife when will I ever learn
She has now told me I will be doing this in the summer

cupan_tae

Counter looks great ! Well done !

CJhaughey

Well done, they look great!
I take it you have read Fu Tung Chengs books "Concrete at Home" and Concrete Countertops?
Lots of good info in them, I bought them a few years ago and still go back to them from time to time for info.
The red one looks almost like Terrazzo with the white quartz.
I like the idea of having a piece of concrete that distinctly captures the local rock formations.

Andrea B.

jimbev wrote: »

The red sand looks great made the mistake of showing my wife when will I ever learn
She has now told me I will be doing this in the summer

Great. Do not underestimate time required. It is something I had available. I will give a breakdown of approximates afterwards once I have completed in full.

Andrea B.

CJhaughey wrote: »

Well done, they look great!
I take it you have read Fu Tung Chengs books "Concrete at Home" and Concrete Countertops?
Lots of good info in them, I bought them a few years ago and still go back to them from time to time for info.
The red one looks almost like Terrazzo with the white quartz.
I like the idea of having a piece of concrete that distinctly captures the local rock formations.

Thanks. Some years ago I had them. For me I think it put me off at the time. This was based on an Irish materials sourcing perspective and an overwhelming amount of options!

I notice on the web now that much of his references are not to generic materials but to his brand, which is a bit offputting.

CJhaughey

I have seen several threads about concrete countertops on here over the years, people always seem to have difficulties sourcing the materials here and I guess its probably due to the overwhelming use of concrete as a building material structurally not as a decorative item.
I would like to see how acid washes and the like hold up here, I really like the look of some of the work he does like the pathways with grasses growing from them and the control joints in copper.
The fibres for reinforcement like nylon and the like are easily made from rope cut into short pieces and frayed apart.

Safehands

CJhaughey wrote: »

I have seen several threads about concrete countertops on here over the years, people always seem to have difficulties sourcing the materials here and I guess its probably due to the overwhelming use of concrete as a building material structurally not as a decorative item.
I would like to see how acid washes and the like hold up here, I really like the look of some of the work he does like the pathways with grasses growing from them and the control joints in copper.
The fibres for reinforcement like nylon and the like are easily made from rope cut into short pieces and frayed apart.

Acid stains and acrylic stains would do well with counter tops, after polishing. It seems that sealing with several applications of a lithium based sealer works best. These can be difficult to get. You may need to go to the States to get them. Acrylic sealers are not so good. PP fibres will only help during the curing phase, after that they don't offer much. Trial and error gets the best results.

Andrea B.

"It seems that sealing with several applications of a lithium based sealer works best. These can be difficult to get. You may need to go to the States to get them. Acrylic sealers are not so good."

Sealers. This has been a difficult area. Too many answers out there and some seem to be commercially driven.
I am going to try Tung Oil.
http://www.hafele.ie/hircat/templates/hafele/Products.asp?param=8596&ig_id=68541

.

Safehands

Andrea B. wrote: »

"It seems that sealing with several applications of a lithium based sealer works best. These can be difficult to get. You may need to go to the States to get them. Acrylic sealers are not so good."

Sealers. This has been a difficult area. Too many answers out there and some seem to be commercially driven.
I am going to try Tung Oil.
http://www.hafele.ie/hircat/templates/hafele/Products.asp?param=8596&ig_id=68541

Yes I know. I am speaking from my experience with companies who specialise in polished concrete. I have no ideas how Tung oil sealer will work on bare, unsealed concrete. It may work, I just don't know. Be careful with sealers. Some may work but may scratch. Some will be affected by hot items or boiling water. The lithium densifiers are designed for this type of work. Look up Liqui-Hard by WR Meadows in the US or "The Ashford Formula".
I don't think they are available here, but they are very good for polished concrete.

tabby aspreme

That looks really good OP , what did you use on the grinder to polish the concrete

Andrea B.

Thanks.I used wet polishing discs from 50 to 3000 grit.

fully floating

Really like what you achieved with the worktop, it definetly looks the part is there any chance you could put up more details about how you achieved it or even links to resources you found useful before starting this project, it has really caught my attention and might consider giving it a go on a small vanity unit top

Andrea B.

Hi.
I will get together list, methods and links when I get a bit of time.

- However to allow you to start and have items ready, the largest tool investment will probably be for a wet grinder.
I bought a Flex Wet Polisher for €200 used. 110v and quality brand.
Not the Ebay Chinese 230v ones.
For a small vanity unit, I imagine a 1day rental would be ok, if you can source?

- Next, you could proceed with ordering a 4" polishing pad kit and velcro backer, but first ensure you know the thread size on your polisher (14mm or 5/8").
I used this seller and the pad and discs are still good.
http://www.ebay.co.uk/itm/151155711042?_trksid=p2057872.m2749.l2649&var=450220404599&ssPageName=STRK%3AMEBIDX%3AIT

I initially bought from an Irish Ebay seller and the velcro pad was crap and disintegrated.

- Next, identify someone with a table saw, that will be able to cut some precise 40mm high strips from melamine panel, so as to border the mould.

-Next, I imagine a plasterers paddle mixer will do for a vanity unit batch.

- Last, I used some fibre, which I did not attempt to source locally, so if you can not source, this is it;
http://www.ebay.co.uk/itm/600g-Bag-Of-Sika-Concrete-Fibres-Free-UK-Postage-/292028428167?

As said, the above are the items with cost and lead times, everything else can be sourced immediately enough.

gutteruu

I've nothing to add, just wanted to say nice job. That came out really well. That red sand sample would get me thinking. I had ideas for an outdoor-ish counter.

Andrea B.

Sorry for being so late back;

-Watch this vid for the templating and border process only.
https://www.youtube.com/watch?v=TG0F7Qe4MzM

-As the strips purchased could be costly, I used a plunge skillsaw with rail to cut my own strips from 3x2 timber.

-I would not get hung up on the silicone.
A clean application, rubbed smooth with finger.
-If you want curved corners, see my solution below with superglued hotel key cards.
-To prevent concrete from blocking screw heads and to allow them to be reused, I put a dab of silicone on heads.

- For steel, I suspended the bars using wire as shown in image. Note that this was a breakfast bar with overhang.
The bars should be clean and dry and away from surfaces or userfacing sides, in case of seepage.
For a small vanity unit, they may not be needed.

-If you are leaving a recess for a sink which is straight edged, use the melamine borders. For an irregular shape, a portion of 40mm deep Kingspan would likely do.

-For the red sample I showed previously, I have images of the B&Q materials I used.
Cement:Sand:Pebbles / 1:3:1
A nice porridgy mix poured in to centre and allowed to flow out to sides.

-Vibration around edge with a hammer drill, 12 inches apart for approx 30 seconds to release air. Do not vibrate from underneath, as apparently it can leave shatter marks in concrete.

-After 4 days remove moulds,
-After another day, flip concrete and wet polish through the grades.

-Last image is the breakfast bar after been dropped in. It is still wet and has a few amethyst stones which I had superglued to melamine.

- It took about 4 days to dry fully before sealing with Tung Oil. I am on my thrid coat, which is probably overkill.
-IMPORTANT. Do not place any items on concrete before sealed. It will soak in and blemish from wood, cardboard, hands...whatever.










Best of luck and please keep posted and come back with any questions!!

oojohoo1

Hi, Just wondering what method did you use to keep holes free for the water faucets?

Andrea B.

oojohoo1 wrote: »

Hi, Just wondering what method did you use to keep holes free for the water faucets?

Hi. I didn't. The faucet is mounted on the sink.

fully floating

Thanks for all the tips, think I'm ready to give it a try just have to get all the bits together think I have managed to source everything so far except the polisher, I have a metabo polisher that will spin at max 4500rpm do you think this may be to fast it would probably be the top speed on your polisher.

Andrea B.

fully floating wrote: »

Thanks for all the tips, think I'm ready to give it a try just have to get all the bits together think I have managed to source everything so far except the polisher, I have a metabo polisher that will spin at max 4500rpm do you think this may be to fast it would probably be the top speed on your polisher.

Sorry, I cannot say for sure.
I assume it is wet?
So easy to do trial samples using rigid plastic packaging as moulds.

slavedave

Nice job on the worktop! Good to see someone other than our USA friends making concrete worktops.

Building an island worktop this week. I sourced white cement, limestone sand, silica sand and white marble 10mm aggregate from Goodwins (also some ladder wire from them for reinforcement). Everything else I sourced from Cemcraft in the UK (an online supplier) - fibres, microsilica, white pigment, Super platiciser and sealer. Broken glass was sourced from a tv stand.
Did a test piece from just cement, sand, glass and aggregate a month ago and it looked fine so decided to go " the full monty" for the worktop.

Cast the concrete yesterday and used large buckets and a mortar mixer from Lidl to make three batches of concrete. First batch was the "face coat" containing the glass, some gravel aggegate and a little bit of broken mirror. Next two batches were backing coats where i substituted marble stones and gravel for the glass component, plus I added the fibre glass to thesebatches. Absolute nightmare to work with in large batches (up to 40kgs) even using the superplasticiser and microsilica (which are meant to make the mixes more flowing). I had planned to make a worktop 1.5 inches deep - not necessary when using glass fibres as reinforcement but I was going down the "bib and braces" line with it. After slaving through the batches I made, I couldn't face mixing a full fourth batch so ended up stopping at just over an inch thickness.

The first "face" coat was very "dry" using the calculate proportions but I cast it in any case, but I ended up adding more water than initially calculated to successive batches just to give me a workable mix. I suspect this will weaken the concrete as a result. My key learning is that I would hire a cement mixer next time because the Lidl handheld mixer, though promising, developed a fault and kept not responding at the most critical points of blending. I would also dose in more plasticiser next time as well.

Will have to wait to see what it turns out like, but I would encourage everyone to at least have a go. I would also think that having two people working together would make things a lot easier.

There are loads of good resources online but it can become a bit daunting because there is so much science involved at times. Well worth spending a few evenings watching beautiful concrete tops being made to get the juices flowing!

stickman1019

I know it’s a long shot but anyone have any interest in resurrecting this thread??

stickman1019

stickman1019 wrote: »

I know it’s a long shot but anyone have any interest in resurrecting this thread??

I did a bit recently
https://www.boards.ie/vbulletin/showthread.php?p=114229685