upcoming extension advice

[mattu27]

Thanks for the replies.

The structural engineer hasn't been brilliant with our enquiries so far. The notes on the floor joists only say 195 X 47 c24 grade timbers bolted with M10 bolts @ 600 centres. I was unsure if this meant the spacing between the joists or the distance of the bolts. Guessing it's bolts as 400 centres is what were going for between the joists as it's a 4m span.

Thanks again Woody, just the Info that I needed. With coach bolts having the inbuilt washer and square section do they need washers on the back aswell?, guessing not.

With regards to padstones, (which haven't been made clear by the SE either) if the inner wall above the piers and initial UB is built with 3.5n blocks I'm assuming it's a pretty wide padstone that will be needed. Would this go across both skins at new roof (soffit) height or just the inner course?

Got the builders round this weekend but don't want to sound completely clueless.

Thanks again.

 

[Leofric]

The structural engineer hasn't been brilliant with our enquiries so far. The notes on the floor joists only say 195 X 47 c24 grade timbers bolted with M10 bolts @ 600 centres. I was unsure if this meant the spacing between the joists or the distance of the bolts. Guessing it's bolts as 400 centres is what were going for between the joists as it's a 4m span.

yes, SE means bolts at 600mm crs ,joists at 400mm crs. Pity engineer isn't more helpful when contacted with queries - they should be.

 

[mattu27]

Hello again, got builders starting on Monday.
They've asked for a final version of the plans so I'm just updating them now.

Just a few questions, are the first floor joists better to be fixed at the UB side by:

1. Notching into recess within the steel and noggins as infill
   
2. Wall plate bolted within the steel and then supported by joist hangers secured to wall plate
   
3. Sat above the steel with new blockwork between joists

We can place the steel at any height but what is the best position in relation to the 1st floor?

Builders have said they want to pocket the joists into the house wall as a wall plate might creak. Seems to make sense to me. Guessing the area is just sealed afterwards to reinstate the closed cavity?

Thanks, Matt

 

[^woody^]

2

 

[mattu27]

Thanks again, just checking the calcs. They say that the beams are to be supported be 3 courses of engineering brickwork.
What class would these be? A or B?
And solid or perforated?

I've emailed the structural engineer and no reply but have asked the builders and they've said that one 7N block is the equivalent to 3 courses of engineering bricks. Which I'm not buying for a minute.

Thanks.

 

[23vc]

Class B Perfs normally, or precast padstones. The 7N block thing may be correct in some circumstances but not others

 

[mattu27]

If they're class B perf I have an abundance left over from the last build!
I was struggling to see how a 7N block is the same as a 50N - 70N engineering brick. The steel at the base of everything is supporting 3 walls, the first floor and the new roof. Think I might go solid class A just as a belt and braces. Are these bedded on mortar as normal?

 

[23vc]

Yeah normal decent strength mix

 

[Leofric]

I would have thought concrete padstones or solid engineering bricks.

 

[^woody^]

It would be solid bricks, as some perforated engineers can be a bit crap for bearing shear due to the holes being near the edge

 

[mattu27]

Gone for Class A solids in the end. No response from structural engineer despite phone calls. Grr.

Thanks everyone.

 

[Leofric]

It would be solid bricks, as some perforated engineers can be a bit crap for bearing shear due to the holes being near the edge

Yes, why would anybody even consider perforated bricks to support steelwork

 

[23vc]

Yes, why would anybody even consider perforated bricks to support steelwork

I’ve used them before, and BCO was ok with it. Probably depends on the situation. But yes, solid is a better suggestion, agreed. The OP has gone belts and braces anyway, so all good.

 

[mattu27]

Evening all, builders have started work and the front of the garage and concrete at the base of the piers has been removed. However, they're now full of water due to the endless rain we've had over the last two days. Seems to be ground water that's coming through from the outside single skin wall as it's running off the tarpaulin roof we've had to make up.

Got a question about the new steelwork that we're hoping to order. The builders are using their steel supplier who says that he can't get an 8M on the lorry for when we need them.

Builders have suggested splitting the steels into two so that the joint is across a pier (5m and 3m respectively) partially for making the lift easier aswell I'd assume, but have now asked if they can have end plates welded on these with 4 pre drilled holes for attaching them together.

Is this the normal method and will building control be ok with it? I'm going to call them tomorrow but the builders would like to order the steels in the morning and I'd like to let them know ASAP before I'm out in a position when they turn up tomorrow expecting an answer.

Thanks, Matt

 

[^woody^]

You need to ask whoever designed the steelwork, not building control.