Tricky kitchen extraction design problem

[Nathanw]

Hi all,
designing the kitchen at the moment and we dont have a clear access to outside for the hob extract pipe. Rather than cut through 5 meters worth of joists or putting it into the neighbours living room i thought i'd run the pipe down the wall behind the cupboards and under the floor to the side access wall. Is this possible without creating an underfloor grease trap i cant get access to and any suggestions on whats needed to make it work.
Many Thanks
Nathan

[Dan the man]

I had this problem and had to build a false ceiling. just made a frame and lowered it about 6 inches, it hid the pipe and also used the new ceiling to put spot lights in!

[Nathanw]

Thanks Dan the man,
problem with that is the kitchen ceiling cant be lowered as we have spent a bit of time and effort in having the roof the same level as our nearly completed extension, so lowering it isnt really an option.
Did you hear of anyone trying to go under the floor when you had the similar problem?
cheers

[Dan the man]

No I dont think I've heard of anyone doing that, the trouble with it is steam and hot gases rise and with the pipe bending down behind the cupboards you might get a problem with condensation and water building up in the pipe, I'm not sure really but I would get advice from a kitchen fitter before you make your plans!

[Perry525]

If your lady will agree, the best way to handle this is go via the floor, and fit the paper grease filter over the cooker hood intake on the outside.

With our filter system, the filter paper is supposed to be fitted on the inside, but it never fits in a satisfactory way, the fan is so powerful it pulls the paper inwards, defeating the object.

We fit the paper grease filter on the outside and add sellotape round the edges to make a tight seal.
This works perfectly and keeps the fan blades and the inside of the pipe perfectly clean.

As far as condensation in the pipe goes, condensation only happens where the pipe is cold, wrap fiberglass round the pipe and add one or two small holes in the bottom of the pipe to allow any water to drip away.