Keeping wall up temporarily after beam installation

[iwanttodiy]

Hi All

As part of my extension project with existing ground floor being open-planned, the design is to build a Goal Post structure, 2 Padstones, 2 Columns, Beam on 2 columns etc to open up a 6 meter wall.

Due to budget constraints and the fact we need to live in the house, we wanted to keep the existing wall up temporarily until the extension is fully erected and sufficiently waterproofed.

I have had builders that want to do the whole project in one go, some builders suggested it is doable, some builders suggested there is nothing holding the wall up once the beams and columns are in and thus unsafe. (If there was no columns, it would be more doable).

Does anyone have any thoughts as to the feasibility? Time scales is probably 1 - 2 months while the extension is build and roof put in with windows, floor concreted plastered etc.

Can i trust the builders who say it can be held up safely?

I would assume if necessary, we could brick and mortar in below the RSJ and existing wall. and add braces/plywood etc either side of the wall to hold it up?

 

[pilsbury]

Seems to me the wall would be only attached at the base, plus there will have to be a gap all around where the slip the goal post in. It will “probably” be sturdy and self supporting but some of the builders clearly aren’t happy with probably when it could kill someone.

Why not just let them knock it down and seal up really well with OSB sheeting and plastic? Be weather tight and won’t kill anyone.

 

[^woody^]

Common sense would be to put the beam and posts in first and leave the wall up.

I would cross those builders of the quote list who say that there is nothing holding the wall up, as they have failed the first "have a clue" test. Failed miserably.

 

[iwanttodiy]

That’s what I though, although worst case scenario, I guess we could board up the opening with OSB and waterproof if we believe safety is a concerns.

I agree, I think I’ll be going with the builders who will aim to put the posts in first and then the beam and if necessary then take down the wall once it’s all in.

Thanks, at least gives me better idea of who to trust.

 

[Footsoldier888]

Okay I think what they might be saying is that the back wall might be very crumbly in the section below where the steel is going in. Perhaps this is old victorian mortar that has turned to dust say and they are concerned the wall itself might come down.

If you have young children you might want to think very carefully about having a defective wall around the place. If the builder is not happy leaving it I would take that seriously as from my limited experience they tend to be quite gung ho in general.

Timescale will be 3 months at least I reckon. It also sounds expensive. If funds are limited consider it carefully as costs can rapidly esculate.

 

[John D v2.0]

Free standing wall with no buttressing or returns, one brick thick? Or cavity construction with wall ties?
I am sure a wall of that thickness would be fine if it were tied in at the sides, but I'm not sure if that still applies with no return at all. If not An SE would probably want to see support posts or some other means of stopping the wall falling. This would be more like temporary works so even acros or scaffolding and wedges would probably be good enough

 

[^woody^]

Whatever the condition or type of wall, if it's wobbly it can be wedged off the posts and beam.

 

[iwanttodiy]

It’s a solid wall, 2 bricks thick’s. Most probably around 5.5m long (once columns are in and some bricks taken out for manuvering.

It would effectively be a free standing wall (no returns) with a wall in the middle coming off that wall like a T shape.

I’ll make sure I check with the builder when he comes on site. I’ve also volunteered to help him with any work he needs so I will be there at all times anyway.

Worst case scenario, as Pilsbury mentions above, OSB and plastic is the way to go temporarily.

 

[Notch7]

For the cost of studwork to block up the opening, I would investigate removing the wall and blocking up.

You could always insulate the temp studwork with celetex - reuse it later in the extension

 

[iwanttodiy]

Whatever the condition or type of wall, if it's wobbly it can be wedged off the posts and beam.

Yes, that’s what I indicated to, maybe using mortar, bricks etc to wedge the wall in as tight as possible, if only temporary. Either way, I should be able to challenge the builders before they come on site as to what they would target, and hopefully fallback to a OSB + plastic if they don’t find it safe.

I suppose my worry is, them leaving it open and I’ll be sitting on the couch with direct garden view

 

[iwanttodiy]

For the cost of studwork to block up the opening, I would investigate removing the wall and blocking up.

You could always insulate the temp studwork with celetex - reuse it later in the extension

That’s a good idea, I generally need the timber anyway, and if the builder isn’t happy to do it, I might be able to get a simple studwork built in a day or so.

 

[iwanttodiy]

Guys

How would you feel about this pricing to fit those beams.

So far the fixed costs are
£1450 (2 5.5 meter PFCs, 1 UB, 2UC with welded baring plates, and bolts, and delivery

£100 - 200 metal works I.e timber joist hangers, misc

£100 Rental of Approx 13 acros and 7 strong boys

£75 genie lift rental, I have been advised 1 can do, but ill budget for 2, so £150

Builder quotes are ranging from £200 a day and 1 builder mentioned he can fit the beams and columns if I helped him in 1 day + 1 day for a smaller joining beam. Thus the quote is approx 2 days £400, but I will budget for any minor problems etc, thus 3 days. £600

Total - £2300

Other builders have estimated about £3500/£2500/£5000 (from my structural engineer). This is ignoring builders who have provided initial estimates for this job of over £10k

The general consensus across all builders is the same process, acros, strong boys, genie lift etc. Are these generally in line with ‘Sane’?

*note* I haven’t budgeted for any major problems, as a major problem, I suppose can cost anything up to a whole house rebuild :S

 

[iwanttodiy]

Ok, property company to do all the works in 1 go.

I asked them about how they will be holding up the free standing wall after the beams and columns have been fitted, as there were worries from other builders about the wall being dangerous as it’s free standing. He laughed, saying the wall will be still pretty strong even if it’s just free standing and there is nothing to worry about.

He’s going to keep the wall up until the end of the build, and knock it down once the extension roof is fully waterproofed

 

[tony1851]

Half-a-dozen 150mm 'G' clamps - or bar clamps - fixed to the lower flange of the beam, hanging down and wedged to the wall will keep it steady; the forces are not that great.

 

[iwanttodiy]

Had a new builder check on my job today. He mentions that it’s not feasible to hold open a 6m opening using strong boys alone, and needs to use 5-6 needles right through to the 2nd floor.

I suggested whether or not a mixture of strong boys and a needle in the middle of the span could be considered which unfortunately got shot down.

3 other builders/building firms have come back to me that strong boys are enough. I checked with Strongboy technical and they mentioned there is no reason why it wouldn’t so long as we match the number of strong boys to the calculated load and use horizontal scaffold braces.

I’m a bit worried now with the new comments, as I have in principle already instructed a building serivce to do this work.