Access to Sub Floor

[johnvarty]

Hi, I am new to this forum and have just bought a bungalow (with a loft conversion) in Edinburgh. It is built on volcanic (andesite) rock, and the floor is (I think "floating") on a sub-floor.

There is access to the sub floor under the stairs, but that access is only to one room. I want to be able to crawl throughout the sub-floor and install under-floor wiring for a stereo - I also want an electrician to do some additional wiring for an extension project.

I notice there are holes in the walls of the sub-floor room - is it permissible to enlarge those holes (removing a few more bricks) in order to gain access to the remainder of the house?

Sub floor is about 3 foot high, and the floor looks like a glassy substance containing rock chips.

Many thanks.

John

 

[ree]

Yes, by and large its possible to knock-thro sub floor walls. Sometimes you have to install a crude lintel, other break-thro's only need to be a matter of removing enough bricks to crawl thro into the blocked off sub-floor area.

The "holes" you see are probably honey combed ventilation holes.

Prepare your tools and an inspection lamp before going down the hatch.

 

[johnvarty]

Thanks Ree. I used to be a caver, so it will be an adventure for me..! I guess if I remove each brick with a cold chisel I should be ok. Just enough room to squeeze through. There are bits of sawdust down there so I may take a vacuum cleaner...

 

[ree]

Remove all wood & paper debris from the sub area.

Easy does it when removing any bricks.

 

[johnvarty]

Many thanks Ree.

Ok - I managed to get into the sub-floor today, and spent an hour with a masonry drill and chisel before resorting to a demolition breaker I bought from Aldi (for another project). The sub-wall section I have removed has nothing loading it and gives me access to the RCD fusebox. The intention is to create a new spur on the RCD box for an external building. I will install the wires, then a qualified electrician can inspect and wire up both ends.

The remaining "breakthroughs" traverse the house and are supporting floor joists, so I will need to be cautious to ensure the floor joists are not left with nothing underneath them. I will install lintels underneath after I have broken through each wall (and keep my family away from the floor I am working under!).

Any advice on the type of lintel I should use? I have seen some 1.2m corregated ones from Wickes which may be suitable (I guess these should be able to distribute perhaps 20-30 Newtons minimum if they are taking footfall loading)? I assume I can just set these in with some ready-mix concrete.. (and keep footfall away, as each one sets!). There is also a DPM (bitumous) that I will replace with a modern plastic one. House is from the 60's...