http://postimg.org/gallery/1z8trzts/8de4fd7a/

Here's a live link to your photos.

Here is a link that might be useful: photos

OK, I have to jump right in here and say those floors with the inlay are gorgeous! Why would you want to cover over them with different wood? If you prefer carpet in the bedroom and LR, then you can put it over top, but please preserve the original floors so that a future owner can restore them.

I would refinish the entry and hallway floors. They are in good shape and will be stunning. To work around the radiator, you should be able to disconnect the piping, pull it out temporarily, lift up the metal escucheons, and sand the area.

Don't worry about a transition "up" from hardwood to carpet. Because carpet compresses when you walk on it, the transition shouldn't be noticeable.

The kitchen looks like it's higher than the hallway. Have you excavated to determine what's in the layers? I'd tear it down to the subfloor, then put tile back on. Ditra will take up less space than cement board, and is easier to work with.

It looks as if you have several different wood flooring products in these areas. The floors with the border look like solid hardwood of some thickness. Although you say that the hallway floor is solid construction, it sure does look like a three strip engineered product, such as that made by Kahrs, Tarkett or some other; that could be floated, glued or mechanically fastened to the substrate. Difficult to say what I'd recommend based on my view of your photos and your description. The questions that come to mind is...do you leave it all down and go on top, as you seem to suggest you want to do...or do you take it all out, including the kitchen floor down to the subfloor and build up from there?

Refinishing it all up is an option with the possibility, as weedyacres suggests, of investigating removal of the kitchen floor down to the subfloor to give you the clearance to produce a flush result between the wood and the new tile. The Ditra system is about the best you can use for the tile job.

Your budget may help determine what you eventually decide to do.

Also, in looking at another pic of your sheet vinyl floor, it appears as if it was glued directly to another hardwood strip floor...is that what I'm seeing?

Hi Weedyacres
Thank you for your reply.

WaterTankHeater:
Do you know if the WaterTankHeater would spill water out if i turn it off and take it apart?

Hallway: The entrance's floor produces loud squeaky sound when i step on it. And it feels hollow when i step on it. The floor seems to be very "thin", looks and feels like it has been sanded many times by the previous owner. (i know its a very bad idea to lay new wood floor on top of it. haha)

Kitchen: Thank you sharing the Ditra idea to me.
Yes, the kitchen floor has many layers. The layer you see in those pictures were actually the third layer of the original floor.

Thank you

Hi glennsfc
Thank you for your reply.

Yes you are right. The hallway's floors are mixed with two different kind of wood. And the entrance's woodfloor feels very "weak" to me.

and Yes, the Vinyl is glued down to other hardwood floor.

After reading you and Weedyacres's comments , should i take away the old hardwood floor in the hallway and replace it with the new one?

Thank you

Hi Weedyacres
Thank you for your advice.

Hopefully i do not need to beef up from below.
Can i use these squeak no more product for joining the subfloor to the joist together?

http://www.amazon.ca/OBerry-Squeak-No-More-Kit/dp/B0006IK8YE

I have used some of them on my living room's floor.
it worked perfectly.

Also,for the kitchen, should i tear up all the layers, put a 1/2 inch plywood right no the subfloor for the Ditra?

From what i know, i need a very solid and stable base for Ditra product.

I will keep you update on it.

Thank you

For the kitchen tile, it depends on what the existing subfloor is. In our current (1920) house, the subfloor is diagonal 1x10s, so to tile we'd have to add plywood, then the Ditra. So tear your kitchen out, see what you've got, and then come back here and we can advise.

And tell us what you find from the basement/crawl space under the entry way floor.

Beefing up the floor from below isn't necessarily a huge deal. It depends on what's below (basement vs. crawl, finished vs. unfinished).

Hi Weedyacres

i have uploaded some new pictures of the kitchen here.
Please have a look.

There are only few squeaky sound in the kitchen.
I believe i can fix it with some "squeak no more" screws.

Another problem, the kitchen's exist door area has a different kind of floor. and that floor itself is a bit higher than the surrounding area.

other than that, the kitchen's floor is quite stable and solid.

so my question is, should i pour some "Level Quick Self Leveling Underlayment" product around the kitchen's floor to smooth out the floor, and then install the Ditra?

or pull all the wood out and then install 1/2 inch T&G plywood on it, and then install the Ditra?

The entrance area:
right below the entrance area is a finished area.
there is no sagging in the entrance area, just heavy squeaky sound.

Thank you for sticking with my problem.
i know i have asked so many question...but i want to get it right and do it right .

Thank you

Here is a link that might be useful: Pictures

You need to do a little more archeological digging still. You need to know the whole construction of the floor before you can decide how best to install something new.

I'd take up that plywood piece in the kitchen and see what's under it. It's higher than the surrounding floor, so needs to go. You should also be able to see from there what subfloor is under the original kitchen hardwood.

It's too bad the space under your entryway is finished, but I'd still do some exploring from below to see what's under there, and to figure out the fix to stop it from squeaking. Is it drywall below or a drop ceiling? I know it probably seems like a pain to tear out drywall, but if you cut out a clean patch, like 2' x the width of the joists, it'll be relatively simple to repair. Just make sure to cut it down the center of the joists so that there's room to screw the patch piece to it later. Cut the hole under the area that squeaks the most, if you can. Have someone walk on and watch the floor from below to see what's moving. It might be as simple as pounding in a couple shims from below, or face-nailing a loose board from above.

You want to find out what's underneath the hardwood. It might be laid directly on the floor joists, or there might be 10" wide boards that the hardwood is nailed to.

Another thought is to take out a board in the hallway, since that's not original and you want to replace it. See what the subfloor is there.

I am a bit puzzled at why, when you've stripped the kitchen down to the original hardwood, it's still higher than the hallway floor. Is your current surface perhaps not the original kitchen hardwood? Peeling back the plywood area will help determine that.

BTW, I haven't heard of that stop squeaking product you linked to, so can't offer any personal opinion.

And don't pour self-leveling compound over top of hardwood. It needs to go over plywood.

Hi Weedyacres
Good to hear from you again.
About the kitchen's floor:
I have replaced the old plywood(It laid directly on the joist) with the new 3/4'' plywood near the exit area. From that, i know the joists are 19 oc. The hardwood locking floors are 3/4" and are laying perpendicular to the joist. There seem to be nothing under the hardwood locking floor .( i could be wrong.)

something like this?
http://sonicchicken.net/blog/wordpress/20071203/hardwood-salvage/

i have attached new pictures of the hardwood locking floor

can i just put 3/8" plywood over the hardwood floor, and then install the Ditra?

Here is a link that might be useful: new pictures

Do you have a close-up photo of the edge of the hardwood before you put the plywood down? It looks, from this photo below, that there's something supporting the hardwood flooring. But i can't tell if it's a perpendicular joist or some 1x6s or something.

Another reason I think you've got a subfloor is that the plywood you added is lower than the rest of the floor, so it means the total thickness is >3/4".

Did you/can you pull up a board in the hall to see if it's got a subfloor under it or if it's directly on the joists?