Croft Structural Engineers Ltd has an extensive knowledge of creating new buildings and homes. We specialise in fitting new buildings into tight inner city sites.
Construction is always evolving. It is vital to keep up with new technologies and Croft Structural Engineers Ltd works hard to ensure that its staff have the knowledge to apply a wide variety of structural forms to a variety of sites.
Over the years Croft has been involved and gained experience in a variety of materials and construction technics;
Masonry walls, now typically cavity with timber floors or precast concrete floors. These types of buildings are simple load bearing structures and suitable up to 4-5 storeys. Higher buildings are possible but the costs escalate and the difficulties of robustness, and horizontal movement joints results in other more economic forms.
Masonry construction and Pre cast concrete floors results in a “heavy” construction. These buildings require “heavy” foundations to resist the loads. The additional excavations costs, particular on brown field sites, can result in more expensive foundations.
Croft Structural Engineers Ltd is a member of TRADA, the timber research association. With our knowledge of timber frames, we recently advised a client to consider a timber frame construction over traditional block work. The change saved the client tens of thousands of pounds.
A development of the timber frame has been the use of LVL panels and solid engineer timbers. Similar to a kitchen block, large panels of timbers are glued together in the factory to make a panel with strong cross linked properties. These panels are then constructed in to walls to allow for rapid construction on site.
Croft used these panels on New build Passiv Haus project.
Structural Insulated Panels SIPS
SIPs buildings are constructed from a sandwich panel that combines an insulation material sandwich between two sheets of ply. The sandwich panels arrive on site as completed walls with doors and windows already formed. This type of construction allows for rapid erection on site. With a 3 bedroom house being completed in 1 to 2 days.
Croft Structural engineers has worked closely with one of the main suppliers of SIPS panels in Europe, Vencil Resil. Croft acted as Vencil Resils UK engineers helping them develop the product within the UK. This has provided us with a strong knowledge of the material and its useage.
Concrete floors columns and walls provide the main structure into which the rooms and cladding are fitted. The heavier weight of a concrete building requires the use of piles more often. Concrete frames are good for awkward shaped sites. A concrete frame building can be begun quickly.
On tight city sites, the cost of Party Walls can run into the tens of thousands of pounds. Recently we completed a 5 storey concrete frame project in a 6m gap between buildings without any awards. By careful design, the foundation depths were specifically engineered not to be deeper than the adjacent properties, thereby negating the party wall awards.
Steel frames are great for large clear span openings such as found in offices or opening plan apartments. The floors are typically concrete sat on a steel frame work of beams and columns
Croft Structural Engineers has a range of knowledge on with the use of modular framed buildings. Timber frames are a flat pack modular building, steel “box” modular construction is very quick and useful.
The production of drawings for construction work is the company’s core role and all designs from 2012 have been Eurocode-compliant. Before any structural design is completed the brief is reviewed with our clients, site visits and inspections are undertaken, and structural calculations are defined for all elements, and only then are the drawings produced.
Construction Over Network Rail and LUL
Croft has completed project adjacent to and even over the top of Network Rail and London Underground Tunnels and assets.
One project that we completed provided a trussed beam over the tunnel sat on 48m deep piles outside the exclusion zone of the tunnel.
Such projects require dealing with the bureaucracy and paper work essential to protect the nation’s infrastructure. The process follows a route of AIP’s (Approval in Principles, also known as form 1’s, followed by detailed design Form 2’s. Additional internal inline designs are normally necessary. The varying levels of CAT II and CAT II checks can be organised by Croft.
Trees Influence on Foundations
Contour map of the depth of foundations due to the local trees. Different trees require varying depth of footings. TPO trees have a Root Protection Area to stay out of.