Plastic Foam Anchoring for Cavity Wall Stabilization

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Solution Overview

Problem

Existing methods for securing double-shell wall constructions are invasive, costly, and inefficient, often requiring the removal of original anchors, drilling numerous holes, and using expensive materials, which can lead to structural instability and damage due to corrosion and weathering.

Innovation Solution

A method involving the introduction of plastic foam through staged filling openings between the outer and inner shells, which permanently connects the two shells without the need for additional mechanical fasteners, embedding existing anchors and sealing them from further rusting, ensuring a strong and stable connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If original wall anchors are removed and replaced with new mechanical fasteners, then structural stability is improved, but the wall structure is damaged and appearance is degraded

Engineering Contradiction:
Improvestructural stabilityVSAvoidwall damage and unsightly marks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the problematic original wall anchors from the wall structure by removing only the necessary portions of the outer wall shell to access and remove the anchors, rather than damaging the entire facade. This selective extraction minimizes harm to the wall structure while achieving the goal of replacing unstable anchors.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies local quality by making precise, localized modifications to the outer wall shell only where anchors need to be replaced, rather than affecting the entire facade. The removed and reinstalled bricks are carefully selected and positioned to maintain the original appearance, applying the principle of minimal invasive intervention.

Inventive Principle:
Principle #3Local quality

2Reliability

If adhesive foam is used to prevent wall bulging, then structural stability is improved, but cost increases and effectiveness is insufficient

Engineering Contradiction:
Improvestructural stabilityVSAvoidcost and material sufficiency
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention uses an intermediary approach by combining mechanical anchors with adhesive mortar as a complementary bonding agent, rather than relying on adhesive foam alone. The mechanical anchors provide primary structural support while the mortar provides secondary bonding, creating a more reliable and cost-effective solution than adhesive foam alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If expanding tie rods are inserted into drilled holes, then structural stability is improved, but cost increases and security is reduced due to friction-only holding

Engineering Contradiction:
Improvestructural stabilityVSAvoidcost and anchoring security
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention replaces the friction-based mechanical holding system of expanding tie rods with a chemically bonded system using adhesive mortar. The adhesive creates a permanent chemical bond between the anchors and the masonry, providing more secure and reliable anchoring than friction alone, while also reducing costs.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If drill holes are made for anchor insertion, then structural stability is improved, but visible marks remain on the facade

Engineering Contradiction:
Improvestructural stabilityVSAvoidvisible drill hole marks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the need for visible drill holes by removing bricks to access the cavity space, inserting anchors through the cavity rather than drilling through the facade, and then reinstaling the bricks to conceal the anchor installation points, thereby eliminating visible marks while maintaining structural stability.

Inventive Principle:
Principle #2Taking out (Extraction)

5Reliability

If outer wall shell is removed, anchors replaced, and shell reconstructed, then structural stability is improved, but labor effort and cost increase significantly

Engineering Contradiction:
Improvestructural stabilityVSAvoidlabor effort and time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention applies partial action by removing only the specific portions of the outer wall shell necessary to access and replace individual anchors, rather than removing and reconstructing the entire outer wall shell. This selective approach significantly reduces labor effort and time while achieving the same structural stabilization goal.

Inventive Principle:
Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method provides a cost-effective and minimally invasive solution that achieves high stability by ensuring the plastic foam adheres to the entire surface, filling cracks and cavities, and preventing further rusting, thus securely anchoring the outer shell to the inner shell without damaging the structure.

Implementation Method 1

The plastic foam adheres to the entire surface, filling cracks and cavities, and preventing further rusting

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

introduction of plastic foam through staged filling openings between the outer and inner shells

Methodology Applied
Scientific EffectFoam expansion: Foam

Data Source

PatentEP3115520B1Method for subsequent securing of inadequately anchored face walls of a cavity wall
Publication Date: 2022.11.30 EVERSLOH NORBERT
  • EP3115520B1 patent drawingFigure 1
  • EP3115520B1 patent drawingFigure 2
  • EP3115520B1 patent drawingFigure 3~4

AI summary

Method for the subsequent anchoring of two wall shells (12, 13) of a double-shell wall construction (1) of an existing building (100) and wall construction (1). The method serves to secure insufficiently anchored or unstable outer wall shells (3), wherein one wall shell (13) serves as the outer shell (3) and the other wall shell (12) as the inner shell (2), and wherein a cavity (5) is formed between the two wall shells. The two wall shells are connected to each other via a plurality of anchors (66). A plurality of horizontally and vertically spaced filling openings (14) are provided in one of the wall shells (12, 13).In the cavity (4) provided with anchors (66) between the existing outer shell (3) and the existing inner shell (2), a plastic material (10) that permanently connects the outer shell (3) and the inner shell (2) is successively introduced through these filling openings (14) in several filling stages (46-48). This permanently connects the outer shell (3) and the inner shell (2). The anchors (66) are embedded in the plastic material (10), and a static post-anchoring of the outer shell (3) to the inner shell (2) is achieved.