Laying a new foundation for conservatory

[stooger]

I'm about to build a DIY conservatory, but want to know how long do I need to leave the finished foundations for, before I can erect the conservatory on them. In other words is there a specified time for allowing for settlement?

[andysarah]

Hi,
The load from a conservatory is so minimal, it really wont be an issue, build the next day. What would be more of an interest is the footing depth? Are building control involved? if so they will ensure they go in correctly, but have a talk with them before you start digging to get an idea of what they are looking for in the way of depths, if not you need to aware that if you have clay soil and trees adjacent to the new building the footings could be going to 2-3m deep. if this is the case I would recommend getting advice from a Structural Engineer or building control before you start digging, else you could end up with a large bill from the ground worker due to building control insisting on deep footings on the day of the concrete pour and you having no alternative but to just dig them.

I have been called in in cases where this has happened, the contractor has asked for a second opinion on the footing depths by an Engineer by which time the hole has fallen in and filled with water and this then started to undermine the main building, a sorry old state!

For warned is for armed!

There are other options to the deep strip footings; firstly get the soil clay content checked to see if it is an issue in the first place by a competent person (plasticity and moisture content); Building control have to assume the worst case if presented with clay that has not been tested so testing could reduce the design depths of footings into clay soils, other option could be Pad and beam, piles, raft etc but once digging has started normally there is no way back!

This has drifted off your question a little but may be of interest to some?
Regards
Andy MIStructE

[westie1961]

[quote="andysarah"]Hi,
The load from a conservatory is so minimal, it really wont be an issue, build the next day. What would be more of an interest is the footing depth? Are building control involved? if so they will ensure they go in correctly, but have a talk with them before you start digging to get an idea of what they are looking for in the way of depths, if not you need to aware that if you have clay soil and trees adjacent to the new building the footings could be going to 2-3m deep. if this is the case I would recommend getting advice from a Structural Engineer or building control before you start digging, else you could end up with a large bill from the ground worker due to building control insisting on deep footings on the day of the concrete pour and you having no alternative but to just dig them.

I have been called in in cases where this has happened, the contractor has asked for a second opinion on the footing depths by an Engineer by which time the hole has fallen in and filled with water and this then started to undermine the main building, a sorry old state!

For warned is for armed!

There are other options to the deep strip footings; firstly get the soil clay content checked to see if it is an issue in the first place by a competent person (plasticity and moisture content); Building control have to assume the worst case if presented with clay that has not been tested so testing could reduce the design depths of footings into clay soils, other option could be Pad and beam, piles, raft etc but once digging has started normally there is no way back!

This has drifted off your question a little but may be of interest to some?
Regards
Andy MIStructE[/quote]

hi, read your response and wanted to ask a question.

the soil in our area ( derbyshire) has some clay, we are considering having a conservatory and some other building works.

our neighbour has some conifers that are about 1 metre from the gable end of our house. they have grown to around 14 foot. they are about 1 foot from our boundary fence.

i removed the slabs that formed a path between our house and his trees and there were no roots evident.

could these trees cause a problem if we wanted to add a conservatory within say 4ft of his trees.

thanks