Attic floor strengthening

Depending on the construction of the roof, you may be able to put some hangers in between the roof rafters/purlins and the "ceiling joists". These could be wood or the metal strap you can buy at the builders merchants. Latter is more convenient.

This sort of thing:-

Looks messier than extra joists but might not matter.

You can put in extra joists of same size between existing as alternative. May not be practical if ceiling has already sagged, matter of degree. Probably not practical to straighten the sag either.

Rule of thumb for joists in inhabited domestic room. Joists @ 16" centres and 2" thick

Depth (in inches) needed is half of span in feet plus 2 So in your case half seven plus two = 6" (rounding up) or 5" rounding down.

So 5"x2" at sixteen inch centres. (As it's not an inhabited room.)

A diagram of how this opening works would be useful...

Under? Not sure I follow... A diagram would help.

If you are planning to use it for extra working space, then you will need to upgrade it to something a little closer to that expected of a floor.

The ideal way to do a floor in a loft is so that it is decoupled from the existing ceiling. Typically you stick a 1" thick piece of timber on the wall plate at the eves between the existing joists. Then you sit the new joists on these, interspersed with the old ones. They will be taller than the old ones, and hence the new floor will be well above the old joists, and the bottoms of the new joists, well away from the old ceiling below.

The last couple of photos here show what it looks like:

So your effective span can be taken as 3.3 m or so (you would probably use two joists at that length - that meet side by side on the supporting wall)

For a 3.3m span using C16 grade timber, you would need 50x170mm cross section timbers to meet modern building regs. However if you are not worried about the floor feeling a bit bouncy (and since its decoupled from the ceiling, you need not worry about it deflecting a bit more than the building regs normally stipulate) you could drop down a bit - to say

A room, 2.1m wide to one side has been opened up into lounge on the other side.

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==================================== Side wall | | Kitchen |Room|Toilet Bedroom ______________|xxxx|_________________ Lounge, toilet and bedroom wall | Lounge | Bedroom | ==================================== Side wall

xxxx = wall removed to open Room into Lounge and hence sag

Joists run Side wall to Side wall (~6.6m) using middle wall for mid-way support.

One obvious solution is to use a support at xxxx from the living side and make a feature eg archway of it. But what does it need to be?

A simple solution is to strap a 6x2" or so beam where the wall xxxx was and overlapping both sides.

Bolt mid way between top and bottom or a number of small screws It will give you a "hump" but it's simple - highly related to what I'll be doing tomorrow...

But the attic is already boarded and if I take an underneath approach I presume that everything can be pushed back up into place?

Does the boarding (t&g) add to strength of the joists or does the additional weight counter this?

I see,

My father did correct a sagging ceiling by jacking up a beam underneath it - he used an array of large wood and wedges, but a couple of acros would work more easily.

Expect some plaster repair work in the vicinity.

If you can support the beam underneath, the final solution will be good.

If it's well nailed or screwed, it will tend to spread the load and tie the adjacent joists together.

I would expect the beam (what size is needed?) would go into the brickwork either end.

The vendor said something to my wife about an arch being removed - it may have been the vendor's wife and I wasn't in on that conversation otherwise I might have had a closer look at the time.