Looking to pick people's brains on propping for a lintel, please. Am I OK to prop joists directly, as described below? If not, what's the "right" answer?
Details.
SWMBO and I moved last year, to a mid-70s dormer bungalow. We're looking to widen an existing internal doorway into an archway about twice the width. Good builders with time right now seem rarer than hens' teeth, and the change is on the critical path of our "big project", so it looks like I get to do it. And I want to make sure I don't anything really stupid when I prop to swap in the new lintel.
The opening we want to widen is ground floor, in a single skin block wall. The wall ends at ceiling height, and is directly under the "wall" studwork of the dormer rooms above. The joists (400mm spacing) run across the wall to where the outer wall originally was (as part of a previous extension, that's now an RSJ; original roof structure is intact).
Now - we don't THINK the wall is load-bearing. When we were talking possibilities, we had a structural engineer take a quick look, and he reckoned that it "almost certainly isn't, but you'd probably put in a lintel anyway". And I've had plaster off, so I can see that the existing lintel over the doorway is a "light use" style, which seems to back that up. Mind, I can also just see the actual joists; they pass 10mm above the wall, but appear to be at least contacting it via some sort of packing. Well - we can't afford to assume, so we'll treat it as though it's bearing some load at least anyway. And I'm wondering how best to prop it while I'm inserting the (1800mm, probably box steel) lintel.
One side of the wall is a concrete float and plenty of access. The other side is chipboard over joists and restricted space (foot of the stairs tight at one side, cupboard at the other; new lintel will overlap the stairs foot). The "best" idea I've had so far is to use acrows to run a scaffolding board or similar across under the overhead joists close to the wall on the concrete side, and support them directly. But I don't know whether propping on one side alone like that is enough to do the job; if it is, how close to the wall I need to keep them; or if it isn't, the best way to go about it.
Thoughts/advice appreciated!
Details.
SWMBO and I moved last year, to a mid-70s dormer bungalow. We're looking to widen an existing internal doorway into an archway about twice the width. Good builders with time right now seem rarer than hens' teeth, and the change is on the critical path of our "big project", so it looks like I get to do it. And I want to make sure I don't anything really stupid when I prop to swap in the new lintel.
The opening we want to widen is ground floor, in a single skin block wall. The wall ends at ceiling height, and is directly under the "wall" studwork of the dormer rooms above. The joists (400mm spacing) run across the wall to where the outer wall originally was (as part of a previous extension, that's now an RSJ; original roof structure is intact).
Now - we don't THINK the wall is load-bearing. When we were talking possibilities, we had a structural engineer take a quick look, and he reckoned that it "almost certainly isn't, but you'd probably put in a lintel anyway". And I've had plaster off, so I can see that the existing lintel over the doorway is a "light use" style, which seems to back that up. Mind, I can also just see the actual joists; they pass 10mm above the wall, but appear to be at least contacting it via some sort of packing. Well - we can't afford to assume, so we'll treat it as though it's bearing some load at least anyway. And I'm wondering how best to prop it while I'm inserting the (1800mm, probably box steel) lintel.
One side of the wall is a concrete float and plenty of access. The other side is chipboard over joists and restricted space (foot of the stairs tight at one side, cupboard at the other; new lintel will overlap the stairs foot). The "best" idea I've had so far is to use acrows to run a scaffolding board or similar across under the overhead joists close to the wall on the concrete side, and support them directly. But I don't know whether propping on one side alone like that is enough to do the job; if it is, how close to the wall I need to keep them; or if it isn't, the best way to go about it.
Thoughts/advice appreciated!
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