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Goalpost RSJ's under deflecting joists


Kilt

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I have a SE plans for improving deflection of first floor joists, which is to cut joists, and insert an RSJ, sat on pad stones..

However due to services and punching through the timber kit to external stone work to build pad stones, the cost of work is significant, and will probably require a massive re-wire, as 80% of electrics run through the joists being cut.

 

An alternative option by builder which is far less invasive (and thus cheaper), is under-slign an RSJ onto vertical steels, which are thunderbolt to the external timber kit walls (which will be beefed up).

We have a screed floor with UFH, so digging down to foundations would be tricky (dangerous). The span is 5m

 

The deflection is bad, however SE said the house isn't going to fall down. So any repair is purely to stop bounce, and level the 1st floor up, as it has also sagged. The repairs don't need to be structural, if that makes sense.

 

I simply can't afford the SE's "invisible" option, as so many services would need to be cut/altered and I don't mind having the RSJs encroaching on the room, but I'm just putting it on here to get some thoughts.

 

 

The bathrooms (above this room) have leaked 2-3 times with previous owners, as I have ripped out one of the bathroom and found evidence of the previous decor/mould. This has to be due to the deflection and movement.

After it was built, the centre joists have sagged/settled by over 30mm, which will have caused some serious issues in a bathroom!!!

 

 

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Screenshot 2020-11-20 at 10.42.44.png

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4 minutes ago, Kilt said:

I have a SE plans for improving deflection of first floor joists, which is to cut joists, and insert an RSJ, sat on pad stones..

However due to services and punching through the timber kit to external stone work to build pad stones, the cost of work is significant, and will probably require a massive re-wire, as 80% of electrics run through the joists being cut.

 

An alternative option by builder which is far less invasive (and thus cheaper), is under-slign an RSJ onto vertical steels, which are thunderbolt to the external timber kit walls (which will be beefed up).

We have a screed floor with UFH, so digging down to foundations would be tricky (dangerous). The span is 5m

 

The deflection is bad, however SE said the house isn't going to fall down. So any repair is purely to stop bounce, and level the 1st floor up, as it has also sagged. The repairs don't need to be structural, if that makes sense.

 

I simply can't afford the SE's "invisible" option, as so many services would need to be cut/altered and I don't mind having the RSJs encroaching on the room, but I'm just putting it on here to get some thoughts.

 

 

The bathrooms (above this room) have leaked 2-3 times with previous owners, as I have ripped out one of the bathroom and found evidence of the previous decor/mould. This has to be due to the deflection and movement.

After it was built, the centre joists have sagged/settled by over 30mm, which will have caused some serious issues in a bathroom!!!

 

 

Screenshot 2020-11-20 at 10.24.50.png

Screenshot 2020-11-20 at 10.39.35.png

Screenshot 2020-11-20 at 10.42.44.png

I don't see this idea being an issue at all - just make sure you do it right.

 

I am going to be doing something similar in an office of ours at some point as the first floor was built with 2x6's where it should have been 2x8's and deflects a fair bit, it is not going to fall down either but it annoys me when you walk across the first floor room.

 

 

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+1

 

I'm sure it will work but BCO might have an issue with the posts bearing on floor screed if there is insulation under it. 

 

Would "decorative" oak beams and posts solve the issue without officially being structural?  

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11 minutes ago, Temp said:

+1

 

I'm sure it will work but BCO might have an issue with the posts bearing on floor screed if there is insulation under it. 

 

Would "decorative" oak beams and posts solve the issue without officially being structural?  

This is my major concern, which led me to post here. Sat on scree and PIR just doesn't feel right. I'd feel much happier if uprights could be dug down to concrete/rebar foundations. Its just the unknown UFH pipe routing, that'd be a really bad day if that got damaged. It was done before we had the property.

 

I think central beam, clad in "decorative [insert current fashionable wood]" is probably an option. It would lend itself well to this property.

 

3 minutes ago, Dave Jones said:

replace with pozi's ?

Joists? with 80% of house wiring going through the current joists (solid ), it'd be an expensive electrician bill. This was my first thought. Nice and tidy and strong.

 

I've discussed making flitch beams with SE, but no-one wants to touch putting new joists in, due to all the wiring and services (I've had 4 joiners/builders and 2 SE's out). I think there's just no room to get new or supplemental joists in.

SE said as well, with the ceiling sagging, the bathroom walls above will have become load bearing.

If ceiling space were totally void, then maybe pois' in would be an option.. just being led here by professional advice and costs.

 

 

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1 minute ago, Mr Punter said:

I think your builder has the right idea.  Steel should be shallower section than timber.  Can you lose the posts in the walls either side?  I would not involve BC as you are just reducing bounce in the floor.

Yeah SE said no need for warrant or planning, as you're "fixing" issues.

 

I initially was under impression that Uprights, would be lost as much as possible in the wall, but that was when I thought they'd be sat on foundations. As builder wants to attach to vertical timber kit, via thunderbolts, the uprights are going to be 100% proud of wall.

 

There's options to maybe build out the wall to totally hide it... 

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I would think that 4" posts would be fine and look no worse than a soil pipe boxing.  You may need chunky bases plate if the screed is weak.  Get the engineer to spec the beam as it would be annoying if it took on a sag.

 

When you install you may need to crank it up over a few days with acrows.

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Thinking out of the box, your first floor plans show bath 2 and en suite with a “ Stud wall?” To bedroom, can you not use steel rods up through that stud wall at intervals to “hang” the floor on and put steel in the loft!

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1 minute ago, Dave Jones said:

all this hassle to avoid making the sparky re run some wires.....

 

I think they are living there so the electric would need to be cut for the duration.  Also new ceiling would be needed and if they change the joists it would be new floor / move out.

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17 minutes ago, Mr Punter said:

 

I think they are living there so the electric would need to be cut for the duration.  Also new ceiling would be needed and if they change the joists it would be new floor / move out.

all of this, except ceiling is already down. Plus we've a biscuit mix wet UFH on first floor (whole reason we have sagging joists I think).

Finally I was give a estimated electrician bill of well over a grand, as it'd be several days work.

 

Don't get me wrong, I'm not trying to do things on the cheap-n-cheerful, a grand doesn't sound much in "Building budgets" scheme of things.. If I had builders that were willing to quote on installing joists, it'd be an acceptable consideration. But none have said it would work, SE's have agreed and would involve some form of access from above.

 

If i could get sparky in, re-wire and have no beams visible, that would be my ideal option. It's just not one that we have budget for or tradesmen willing to do. 

Edited by Kilt
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27 minutes ago, Mr Punter said:

I would think that 4" posts would be fine and look no worse than a soil pipe boxing.  You may need chunky bases plate if the screed is weak.  Get the engineer to spec the beam as it would be annoying if it took on a sag.

 

When you install you may need to crank it up over a few days with acrows.

SE spec 200mm (+7")which is what builder also initially stated.

 

I'm playing around at moment, with possible bringing whole wall out 200mm, and building "niche's" or bookcases into the wall or just a meter section to enable furniture to go against steel.

Edited by Kilt
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33 minutes ago, joe90 said:

Thinking out of the box, your first floor plans show bath 2 and en suite with a “ Stud wall?” To bedroom, can you not use steel rods up through that stud wall at intervals to “hang” the floor on and put steel in the loft!

ha ha! I like your thinking. 

 

Maybe when we get a new roof? We'd prob need a 18m long steel in the roof to support the pulling up beam.. roof beams are 300 years old and riddled with woodworm, I worry then can handle my weight when I'm up there.

Edited by Kilt
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18 minutes ago, Kilt said:

ha ha! I like your thinking. 

 

Maybe when we get a new roof? We'd prob need a 18m long steel in the roof to support the pulling up beam.. roof beams are 300 years old and riddled with woodworm, I worry then can handle my weight when I'm up there.


Oh dear, if it’s an old cottage or something then an oak beam across the room downstairs will be more in keeping , what are the walls made of? Brick. (I hope) so beam could be set in them or oak angled brackets!

 

rather than steel rod just steel cable, say 10mm threaded through and up to loft fir when you get that far, remember it’s not structural just a means of reducing “sagging”.

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3 minutes ago, joe90 said:

what are the walls made of?

its a timber kit internally. its a (very bad) barn conversion (circa 2000). New timbers throughout, except for roof joists and rafters. They're original, for some reason.. amount of woodworm, I'd have replaced them, it's not like its a listed building. 

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21 minutes ago, joe90 said:

@Kilt Do you fancy an oak beam as a solution? Is the UFH under the timber frame walls either end?

As the span is 5m, I’m not sure oak would be able to cut the mustard and help prop up the joists, and rooms above. 

also I don’t know what costs are oak v’s steel.

 

also finding builder who’d use it. 
 

With covid and it barmy for trades, it’s taken 6m just to get to quote stage. 
 


 

Timber frame is sat on foundations, scree/UFH within the timber kit. 

Edited by Kilt
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