Victorian Floors Help

[Richard]

This is follow up from one of my earlier posts. Thanks Alex for your advice on toothing the brickwork. I have another question regarding this job, I hope somebody will be able to understand my ramblings and and help me out.

Here goes:

I am blocking up a door way to beome part of a load bearing wall. I plan to then remove the middle section to form an archway. The existing wall has a solid floor one side (concrete)and a part wooden suspended floor and part solid floor the other side. The house has been converted and the part wood floor and part concrete floor is a hallway and a front room converted into one which is now my dining room.

If I pull up one of the floorboards in the dining room I can see the bottom part of the wall I plan on knocking down run all the way down to the ground and therefore I can see what will be supporting the RSJ at one end of the wall. However, the door span we plan to brick up which will become the support for the other end of the RSJ spans the solid floor. I've done some digging and it looks like there is a good couple of inches of concrete laid directlty on the ground, is this possible?

If so in the old days did builders just dig out areas that were going to have suspended wooden floorboards and where there were going to be solid floors just lay concrete down? I don't understand how this works???

I'm trying to ascertain if whatever is underneath the door span (concrete floor) which I think is the ground, will be man enough to support a load bearing wall as the RSJ will be terminating on this new brickwork.

This is probably as clear as mud!!!!

Any help appreciated, I dont think I'd be flavour of the month if half the house fell down!!!

Cheers

Richard

[Lobster]

Dunno, but I think you're right to question it. Why not fit a longer RSJ which spans the entire opening, ie the new archway as well as the old doorway? That way you'd know that the end of the RSJ is definitely supported by solid wall. Might be less hassle to pay £200 to a structural engineer to advise you though!

One issue I faced which may or may not apply to you... when I recently bricked up an original doorway in a loadbearing wall dated about 1900, I found there was no lintel there, ie the wooden door frame was taking the load. So I couldn't just rip out the doorframe and brick up; I had to support the wall with an acrow prop first. All I'm saying is, it's worth ripping off the plaster above the door and having a look beforehand!

David

[Richard]

I have actually employed a structural engineer however his report did not detail this potential problem although we did verbally talk about it. I just ran your idea past him, I thought it was a great idea but he basically said how can you be sure that there's a proper footing under the other part of the wall, that part of the wall was new and was built where a staircase and cupboard once was and bonded into the old. I reckon he was just upset that he didn't come up with that idea!!!! He does however have a point so it looks as though I'm going to have to get one of those big neumatic drill things and start digging to put in a footing.

Cheers for this.

Richard

[Alex]

It's a bit late and eyes are a bit fuzzy, but I think I know what you're saying. If you're getting building regs for this, the BCO will want to see some evidence of what's there already. Most likely the cheapest option is to get a good footing in at each end, build a brick pier off each of these, and site your RSJ on these.

Of course, I may have misunderstood your situation (most probable in fact). I suppose what I should say (as has already been said, rendering this post useless) is that you can't (in theory) rely on the wall having adequate footings or for the solid floor to be adequately supported.

Alex

[N. Thornton]

of course. I dont understand whats confusing about that.

Well, the ground holds the house up, so one would expect so. Concrete ground floors were laid on the ground, not over a suspended structure. Modern deep foundations are to guard against the chance of movement and consequent cracking, not to prevent collapse. 1900 houses mostly have very little in the way of foundations, and some have none.

In 1900 they would almost never have bothered with ironwork, theyd either use wood or form a brick arch for the support - which is whats youre doing anyway. Brick arches work well, as long as you have some width of brickwork either side of the arch, since arches cause sideways forces.

In some old houses I've seen they didnt bother with anything, just relied on the brickwork to support itself - it very nearly always does, but of course it isnt recommended. Seen one built like that start to collapse once.

Now what build regs has to say about it is another question, and you'll need to conform to those.

Regards, NT