tinan did a DIY concrete kitchen countertop. Search GW .

Yes I poured concrete over tile. You don't need to remove your laminate, just sand it to scuff it up so the concrete can bond better, and use a repair-grade concrete that is meant to bond to things. If the laminate is damaged or easy to remove by all means removed it but I think you'd need to add a waterproof layer over the MDF layer since concrete is porous, you'd get moisture causing swelling. I poured the concrete right over the ceramic tile countertop which was already waterproof. Where I switched out my sink, I had to add in a plywood section since the old sink was wider, so I covered that with waterproof building paper (used for roofing etc). You could cover MDF or particle board with roofing paper to prevent moisture intrusion if you need to remove the laminate. Personally I would just sand/scuff up the laminate and use the type of concrete made for repairs to horizontal and vertical surfaces (it usually contains polymers that make it stronger and bond to substrate more easily).

Basically I build molds using 1x4's, sprayed them with cooking spray to prevent cement adhering, then mixed up the concrete I used "Cement All Rapid Set" sold at Home Depot and Lowes. It does set VERY quickly so I recommend buying the additive that extends setting time so you have more time to work with it. I'd never used concrete before so I made some mistakes you can learn from - though it all turned out fine in the end.

1. use the additive for extended set time
2. follow the manufacturer's directions for mixing and use
3. seal your molds with caulking, I thought mine were tight enough to be OK but I had a couple of leaks because I was too lazy to caulk, and that was a big mess!
4. if You don't want knot-imprints in your concrete spend the extra for melamine boards. I used the cheap pine type and had a few interesting marks to sand out.

In the thread below you will see pics of my mistakes - the part by the sink was caused by a leak in the mold, the concrete mix leaked out the bottom (I did have plastic down but it was a mess) and later had to be patched. It turned out OK but if I had caulked the molds in the first place it would not have happened.

Self leveling concrete would perhaps have been easier to get a smooth surface with but others warned me it would crack and no be ideal for the thin overlay I was doing, so I went with this super strong repair material. It's been in for 6 months now and I haven't had any issues with cracking, staining or anything. There are a couple of fine hairline cracks that formed when it dried because I poured it right to the wall with no expansion joints and the countertop is wrapped around the whole room. I don't mind these, and they can be filled with a slurry of cement and water to fill before sealing. I didn't bother, I just sealed it as is and the hairline cracks are filled with the sealant so dirt does not get in. I think it adds character.

I considered acid staining but decided I was done with the project and liked the light gray color as is!

Here is my before/after "reveal"

Here is a link that might be useful: Cement All

Tina, I am SO impressed! My husband is a concrete guy-he's made countertops for others, made our hearth for our woodstove-and make every type of statuary & memorial you can imagine.

So do you think I ever got my concrete countertops I'd dreamed of? I ended up putting on tile, which I love, but I made the grout lines way too wide. I've fantacized about tearing out the tile-but like you, just don't have the will. I honestly think I might be able to get him to pour me countertops like this-my kitchen layout is similar. I don't have an undermount sink, so I think it'd be easy to make the drop in hole.

I do want to acid stain mine-actually I'd love to make it look like wood. I really think this might be a job I can get him to this winter! Would just need to convince him to use a different mix than he uses for pouring 'virgin' pours.

Rough spots can easily be sanded out with a power sander, and you can sand it all and stain some day if you chose.

I really, really want to add a copper border-I'm thinking of 1/2" copper pipe for a type of bullnose. Might have to try that out. Your kitchen reno is amazing.

Pesky I was able to do this in a weekend by myself and have never mixed concrete before in my life! I am sure your expert husband could make you amazing countertops in no time. It took me a few hours to build the molds, next afternoon I poured the concrete, following day fixed my mistakes and then the next weekend sealed it.

I do want to find the time soon to perfect it with some sanding down but I still am happier with it than our yucky bumpy tile.