Mon - Sat 09:00-18:00
+ (44) 07443904751
info@structuralengineercalcs.com
New Clients

610+

Projects

1287+

Trusted by

20.000+ Customers

Foundations

Raft foundations (sometimes known as Mat Foundations) are a large concrete slab which can support a number of columns and walls. The slab is spread out under the entire building or at least a large part of it which lowers the contact pressure compared to the traditionally used strip or trench footings.

Difficult ground conditions can be a problem when constructing foundations that is where foundation rafts can be the perfect solution. Grounds can have low bearing pressure capacity or previous materials used have had a significant impact on the ground condition. Distributing the weight of the building over a larger space, foundation rafts reduce pressure on the soil, they can be economical solution to reduce the foundation depth in shrinkable clay, adding a thick stone sub-grade beneath it. Rafts designed to prevent any cracking in the building.

Raft foundation is usually used for large loads, which is why they are so common in commercial building which tend to be much larger, and therefore heavier, than domestic homes It is also preferred to use raft foundation when the soil has a low bearing capacity so the weight of the building needs to be spread out over a large area to create a stable foundation . In addition, it is recommended to use raft foundation if the walls of the building are so close that it would cause the individual footings to overlap.

Please ensure that the excavation for the foundations will not weaken any adjacent foundations or neighbouring ground

Excavations may fall under the Party Wall Act.  Please seek specialist advice.

We need the following information for a raft foundation design:

A site investigation report.

Sketch drawings with dimensions of the building elevations.

Details of any drainage and trees close by.

Also, for extensions we will require details of the existing house foundations.

 

Pile foundations are principally used to transfer the loads from superstructures, through weak, compressible strata or water onto stronger, more compact, less compressible and stiffer soil or rock at depth, increasing the effective size of a foundation and resisting horizontal loads. When designing the piles, the piles loading need to be calculated beforehand. If the ground conditions dictate which makes piled to foundations absolutely necessary. Ground conditions are the key when designing piled foundations for example if the ground is in poor condition and the soil is not suitable to prevent excessive settlement, pile foundations can be an economical solution.

Information required to work out pile foundation loading:

Architectural layouts.

 

An eccentric foundation is a foundation whereby the wall sits on the outer edge of the foundation. The entirety of the foundation and the wall will therefore be wholly on the building owner’s land, meaning that they are not only getting a larger extension, but they are also reducing the impact of their proposed work on the adjoining owner’s property.

A typical foundation differs from this as the wall sits at the centre of the foundation. This type of foundation can either be placed astride the line of junction, thereby acting as a Party Wall. Alternatively, it can also be placed so that the wall is wholly on the building owner’s land, with the outer edge of the foundation projecting onto the adjoining owner’s land.

Eccentric foundations are used in a number of different situations during Party Wall works:

When a building owner wants to build their proposed wall right up to the line of junction, thereby maximizing the space of their proposed extension.

When the adjoining owner already has their own extension in place, built up to the line of junction. Thereby, meaning a typical foundation design isn’t feasible.

If the adjoining owner’s foundation projects into the building owner’s land, meaning a typical foundation is not possible.

Where the adjoining owner doesn’t want any projections into their land, as they intend to undertake a similar extension in the future.

Please ensure that the excavation for the foundation will not undermine any adjacent foundations or neighbouring ground.

Excavations may fall under the Party Wall Act.  Please seek specialist advice.

We need the following information to design an eccentric foundation

Architectural layouts and elevations of the property.

The distance between the outside of the wall and the boundary (if it is not on the boundary).

Site investigation report.

 

Ground beams are structural elements are that transfer loads imposed along their length to their end points where the loads are transferred to columns, walls and foundations.

Ground beams are beams that are designed to span between pad foundations and piles.

The advantages of using ground beams are that they are quicker to install than conventional footings, and allow uncertainties regarding ground conditions to be overcome. They also create a very accurate bearing level, reducing the amount of leveling up that is required prior to starting to build up the superstructure.

Ground beams may be used to support brickwork and block-work, but may also be used at the edge of in situ concrete floor slabs, where they form permanent shuttering. They tend to be square or rectangular in section.

Pleas ensure that the excavation for the foundations will not weaken any adjacent foundations or neighbouring ground

Excavations may fall under the Party Wall Act Please seek specialist advice.

We need the following information to design a reinforced concrete ground beam:

The position of the ground beam needed.

Architectural layouts and elevation details showing the height of the walls.

Details of the extent of the poor ground or other feature that the ground beam is to span over.

 

How can we help you?

Dont be shy, Just tell us about yourself and we’ll figure out the best option for you and your project.
Receive regular updates on the latest tutorials
Get a quote

©2021 Structural Engineer Calcs Ltd