Different floor levels - kitchen and dining room

[307camel]

Hi guys,

So.....dining room is at the back of the house, leading on to the kitchen and then the hallway.

Dining room floor is currently 30mm higher than the rest of the downstairs. Plan is to tile right the way from front door to dining room (which provides the back door).

After what seems too much effort I have eventually removed the dining room tiles. Underneath I have found what looks like a concrete (sandy with small stones) sub layer which seems to be coated with a very thing black layer. The sub layer is roughly 30mm thick. Please see pics.

Under the sub layer, there just seems to be sand??? Is this correct?

As I plan to make the downstairs all one level I was wondering if you guys would recommend breaking it all up and starting again. Not only will this allow me to achieve the same level but it will also mean that I will not have to scrape this TOUGH adhesive off of the floor.

Also, for the concrete sub layer, what would you recommend in terms of:

i) Under base - i.e. hardcore or just sand?
ii) What thickness
iii) What kind of mix?
iv) Should I just make the concrete up to the final desired level or leave it a few mm short and then use some latex self levelling compound?

Any help much appreciated.

Please see pics as this might help decipher some of the above.

Thanks again.

Sub Layer Chuncks

Sub layer chunks.jpg (652.99 KiB) Viewed 2135 times

Cross section of sub layer and floor

Cross section of sub layer and floor.jpg (628.68 KiB) Viewed 2135 times

Floor with remaining adhesive

Floor Adhesive.jpg (348.39 KiB) Viewed 2135 times

[haveagohero]

Looks like bitumen on top of the screed. Does the screed sound hollow when you tap on it? does it look like its crumbling? what
was the condition of the old tiled floor like? any cracked tiles? cracked or crumbling grout? If the answer to any of these is yes then take the floor up and get a firm in to re screed it for you, leave it slightly lower than the adjoining floor so it can be self levelled before you tile. Make sure that the screed is completely dry before you start tiling (8 weeks ish)

[307camel]

Thanks for your response.

The screed does sound hollow in some spots. Surprisingly, there is not any cracks in it and the tiles or grout were not cracked and did not show any other signs of damage. The floor is not level and this showed with the poor finish of the tiles.

I am considering taking it up, putting hardcore in (the old tiles), doing a concrete base (5:1 Ballast and cement) on top of insulation and a membrane.

Its interesting you advise to put self levelling compound on the concrete rather than just taking the concrete up to the required level? In future, if I ever want to change the tiles but do not want to scrape adhesive off the new level is it possible to easily get the self levelling compound off (ie back to concrete), rather than spending ages removing adhesive?

How easy is it removing self levelling compound?

Many thanks