Secant Interlock Ready Reckoner App

The Walsh Secant Interlock Ready Reckoner App has been created to allow you to visualise diameters and spacing for secant piled walls with reference to current best practice guidance CIRIA C760 and ICE SPERWALL.

The app parametrically generates and visualises a 3D model and 2D plan view plot of a secant piled wall with geometry and resulting values calculated in real-time. This is of particular use to anyone involved in the design and construction of deep basements including structural engineers, geotechnical engineers and contractors as well as Estimators and Quantity Surveyors, 

Please note, the app has been optimised for use on a Desktop and you will need to agree to the terms and conditions below to access.

To Access and Use the Secant Interlock Ready Reckoner App

Please confirm that you have read following Terms & Conditions with the button at the bottom of this window.

By using the Walsh Secant Interlock Ready Reckoner app (App) you agree to the terms of this End User Licence Agreement (EULA) which will bind you.

If you do not agree to the terms of this EULA, you may not access or use the App.

Who we are and what this EULA does

We, Walsh Associates Limited, company number 02339267 of The Clove, First Floor, 4 Maguire Street, London, England, SE1 2NQ (Walsh, we, us etc.) license you to use the App and any updates or supplements to it as permitted in the terms of this EULA and the ready reckoner features provided through it (Service).

Your privacy

Under data protection legislation, we are required to provide you with certain information including who we are, how we process your personal data and for what purposes and your rights in relation to your personal data and how to exercise them. This information is provided in the following link and it is important that you read that information.

How you may use the App, including how many devices you may use it on

In return for you agreeing to comply with the terms of this EULA you may:

  • view, use and display the App and the Service only in accordance with the terms of this EULA; and
  • receive and use any free update of the App incorporating “patches” and corrections of errors as we may provide to you.

Age restriction

You must be 18 or over to accept the terms of this EULA and use the App.

Changes to EULA terms

We may need to change the terms of this EULA to reflect changes in law or best practice or to deal with additional features which we introduce.

We will endeavour to give you at least 30 days’ notice of any change by notifying you when you next start the App.

If you do not accept the notified changes you will not be permitted to continue to use the App and the Service.

Update to the App and changes to the Service

From time to time we may automatically update the App and change the Service to improve performance, enhance functionality or address security issues.

If someone else owns the device you are using

If you use the App on any device not owned by you, you must have the owner’s permission to do so. You will be responsible for complying with the terms of this EULA, whether or not you own the other device.

Licence restrictions

You agree that you will:

  • not rent, lease, sub-license, loan, provide, or otherwise make available, the App or the Services in any form, in whole or in part to any person without prior written consent from us;
  • not copy the App or Services, except as part of the normal use of the App;
  • not translate, merge, adapt, vary, alter or modify, the whole or any part of the App or Services nor permit the App or the Services or any part of them to be combined with, or become incorporated in, any other programs, except as necessary to use the App and the Services on devices as permitted in the terms of this EULA;
  • not disassemble, de-compile, reverse engineer or create derivative works based on the whole or any part of the App or the Services nor attempt to do any such things; and
  • comply with all applicable technology control or export laws and regulations that apply to the technology used or supported by the App or any Service.

Acceptable use restrictions

This App provides information based on standard engineering principles and data. However, you acknowledge and understand that the App and Services may not cover every possible scenario or consider site-specific conditions, and as such you agree to verify all results obtained from the App and Services with a qualified expert using appropriate professional expertise and against all relevant industry standards.

The App is a ready reckoner tool to assist you with indicative scheming work only and is not to be used for any detailed design work. The App is not a substitute for professional judgment or consultation with qualified experts. You are responsible for ensuring the accuracy and appropriateness of any calculations, designs, or decisions made using the App or any Service.

You are encouraged to use the App with caution and take appropriate precautions in light of the above disclaimers and you acknowledge and agree that, except as otherwise expressly stated, we shall have no liability arising out of or in connection with any use of the App or Services.

You must:

  • not use the App or any Service in any unlawful manner, for any unlawful purpose, or in any manner inconsistent with the terms of this EULA, or act fraudulently or maliciously, for example, by hacking into or inserting malicious code, such as viruses, or harmful data, into the App or any Service;
  • not infringe our intellectual property rights or those of any third party in relation to your use of the App or any Service (to the extent that such use is not licensed by the terms of this EULA);
  • not transmit any material that is defamatory, offensive or otherwise objectionable in relation to your use of the App or any Service;
  • not use the App or any Service in a way that could damage, disable, overburden, impair or compromise our systems or security or interfere with other users; and
  • not collect or harvest any information or data from the App or Service or our systems or attempt to decipher any transmissions to or from the servers running the App or any Service.

Intellectual property rights

All intellectual property rights in the App and the Services (including all branding in respect of the same) belong to us and the rights to use the App and Services are licensed (not sold) to you. You have no intellectual property rights in, or to, the App or the Services other than the right to use them in accordance with the terms of this EULA.

Our responsibility for loss or damage

We do not exclude or limit in any way our liability to you where it would be unlawful to do so.
This includes liability for death or personal injury caused by our negligence or the negligence of our employees, agents or subcontractors or for fraud or fraudulent misrepresentation.

When we are liable for damage to your property.

If defective digital content that we have supplied damages a device or digital content belonging to you, we will either repair the damage or pay you reasonable compensation. However, we will not be liable for damage that you could have avoided by following our advice or instructions.

We are not liable for certain losses.

The App and the Services are provided “as is” and without warranties of any kind either express or implied to the fullest extent permissible under applicable law. While efforts are made to ensure the App’s availability, we cannot guarantee uninterrupted error-free operation, that it will be free of viruses or other harmful components or that the App will meet all of your requirements. We will have no liability to you for any loss or damage suffered or incurred by you as a result of the App’s unavailability, any error or virus in the App or a failure to meet your requirements.

The App is only to be used in accordance with this EULA and you may not use the App for any purpose that breaches its terms. We will have no liability to you in respect of any losses, damages or costs suffered or incurred by you as a result of your breach of this EULA.

Additionally for business users,

subject to the section “We do not exclude or limit in any way our liability to you where it would be unlawful to do so” above, if you are a UK headquartered entity (and not an individual residing within the UK acting for purposes which are wholly or mainly outside your trade, business, craft or profession), we also expressly exclude the following types of loss or damage:

  •  loss of profits;
  •  loss of sales or business;
  • loss of agreements or contracts;
  • loss of anticipated savings;
  • loss of or damage to goodwill; and
  • indirect or consequential loss.

Please back-up content and data used with the App.

We recommend that you back up any content and data used in connection with the App, to protect yourself in case of problems with the App or the Service.

We may end your rights to use the App and the Services if you break the terms of this EULA

We may end your rights to use the App and/or Services at any time by contacting you if you have broken any terms in this EULA in a serious way. If what you have done can be put right we will give you a reasonable opportunity to do so.

If we end your rights to use the App and Services:

  • You must stop all activities authorised by the terms of this EULA, including your use of the App and any Services; and
  • We may cease providing you with access to the App and any Services.

We may transfer this EULA to someone else

We may transfer our rights and obligations under the terms of this EULA to another organisation. We will always tell you in writing if this happens and we will ensure that the transfer will not affect your rights under the contract.

You need our consent to transfer your rights to someone else

You may not transfer your rights or your obligations under the terms of this EULA to another person.

No rights for third parties

This EULA does not give rise to any rights under the Contracts (Rights of Third Parties) Act 1999 to enforce any term of this EULA.

If a court finds part of this EULA illegal, the rest will continue in force

Each of the paragraphs of the terms of this EULA operates separately. If any court or relevant authority decides that any of them are unlawful, the remaining paragraphs will remain in full force and effect.

Even if we delay in enforcing this EULA, we can still enforce it later

If we do not insist immediately that you do anything you are required to do under the terms of this EULA, or if we delay in taking steps against you in respect of your breaking this EULA, that will not mean that you do not have to do those things and it will not prevent us taking steps against you at a later date.


The invalidity, illegality or unenforceability of a provision of this EULA does not affect or impair the continuation in force of the remainder of this EULA.

Entire agreement

This EULA constitutes the entire agreement between us and supersedes and extinguishes all previous agreements, promises, assurances, warranties, representations and understandings between us, whether written or oral, relating to its subject matter. You agree that you shall have no remedies in respect of any statement, representation, assurance or warranty (whether made innocently or negligently) that is not set out in this EULA. You agree that you shall have no claim for innocent or negligent misrepresentation or negligent misstatement based on any statement in this EULA.

Which laws apply to this EULA and where you may bring legal proceedings

This EULA is governed by English law and you can bring legal proceedings in respect of the App and/or Services in the English courts.

Thanks to Richard Ball, Molly Machin and for their work developing this app.

If you have any comments or suggestions, please email

Taking Sustainability Seriously

Sustainability is in our DNA and we have our own ambitious goals to achieve Net Zero as a business and with our designs. With innovative in-house monitoring tools, Walsh clients have seen on average reductions of 10-20% total embodied carbon, with some of our flagship work achieving 60-70% reductions compared with baseline figures.