Couple of extension questions

[Ljc1980]

Hi all, just planning a side extension -single storey and have few queries while I'm trying to get plan formulated in my head!

Suspended floor (as on sloping site) - should joists run the 5m length of extension, supported on sleeper walls, or across the 3m length attached to house with ledger board.

Walls - was planning block outer and block inner - purely as I seem to be able to find more info on how to build this rather than wooden frame - is this wise?

Current house is rendered to the ground (see pic) - should I copy this as I thought it would bridge the dpc?

Does anybody know any good step by step guides for the roof construction - simple lean to pitched roof.

Untitled

• Ljc1980
• 25 Oct 2014
• 5

 

[freddiemercurystwin]

How much is the slope? Begs the question why you want to do suspended timber.

Is your existing floor suspended timber? There looks to be some vents at low level so I guess it is, you may need to consider this when you do your floor, do you have any vents in the gable wall?

Though if you do end up going timber suspended then run your joist the shortest span.

Traditional masonry cavity walls is the way to, forget timber frame.

Technically rendering down past the dpc does bridge the dpc though realistically so what if a bit of moisture is absorbed into the outer skin. Though BC may not be impressed. Alternatively you would just do brick plinth. Or blockwork painted.

 

[Jaxta1]

From my rough measurements, I think the internal floor level is 200mm above outside ground level at the top end, and 600mm where the far end of extension would be - therefore drop of 400mm.

I thought timber because laying a slab would mean I had 600mm of concrete and associated sub base up against external wall. With it being timber floor on other side of wall I thought this May be too much pressure to place on wall?

Also I was worried that the dpc of the extension would bridge that of existing house?

If these concerns are no issue I'd be delighted if I could do slab floor!?

There are 2 vents just below floor level on the gable -presume I'd have to duct these?

Many thanks

 

[Jaxta1]

If I did go suspended floor, I would be looking to attach a ledger to the side of the house and install joist hangers to it. On the other side (3m span) I'd put joist hangers on the internal block wall.

Would it be an issue if the ledger board on house covered the 2 vents on the gable? I'm not sure how I could avoid this!