Movement Control Screed for Masonry Moisture and Stress Management
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Solution Overview
Problem
Existing masonry construction methods fail to effectively manage moisture and movement between dissimilar wall materials, leading to potential rotting of wooden structures and cracking of masonry coatings due to inadequate drainage and stress relief at wall transitions.
Innovation Solution
A movement control screed that functions as both an expansion control joint and a weep screed, featuring flanges and ribs with varying depths and perforations to accommodate different masonry coating thicknesses, providing a moisture barrier and facilitating drainage while allowing for movement and stress relief between masonry coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If foundation weep screeds are installed to provide drainage and prevent moisture contact with exterior walls, then moisture protection is improved, but the ability to accommodate movement and prevent cracking in masonry coatings is insufficient
Solution Approach 1:
The patent combines the functions of a foundation weep screed (drainage and moisture barrier) with an expansion control joint (movement accommodation and crack prevention) into a single integrated device. The flange provides moisture barrier functionality while the ribs with varying depths create expansion joints that accommodate movement, allowing both functions to coexist in one component rather than requiring separate installations.
Solution Approach 2:
The screed device performs multiple functions simultaneously: it acts as a moisture barrier through the flange, provides drainage pathways through the rib structure, accommodates thermal expansion and contraction through deflectable ribs with varying depths, and prevents cracking by creating controlled expansion joints. This multi-functional design eliminates the need for separate components for each function.
2Reliability
If expansion control joints are used to accommodate movement and prevent cracking in masonry coatings, then crack prevention is improved, but effective drainage and moisture barrier functionality are insufficient
Solution Approach 1:
The patent integrates the expansion control joint functionality (ribs with varying depths for movement accommodation) with foundation weep screed functionality (flange for moisture barrier and drainage) into a single device. This allows the same component to provide both crack prevention through controlled expansion joints and effective moisture protection through the flange and drainage pathways.
Solution Approach 2:
The screed device simultaneously provides expansion joint functionality through its rib structure with varying depths that deflect to accommodate movement, and moisture barrier/drainage functionality through its flange design. This universal design ensures both crack prevention and moisture protection are achieved by one component rather than requiring separate systems.
3Strength
If wall transitions are constructed with dissimilar materials (wood and concrete) to meet building code requirements for wind and impact resistance, then structural strength is improved, but moisture management and movement accommodation at the transition point are insufficient
Solution Approach 1:
The patent applies different rib depths at different locations of the screed to address local requirements: deeper ribs on one side accommodate greater movement where needed, while the flange provides localized moisture barrier functionality at the wall transition point. This localized variation in rib depth allows the device to adapt to the specific movement and drainage needs of dissimilar material transitions.
Solution Approach 2:
The screed device acts as an intermediary component installed at the transition between dissimilar wall materials (wood and concrete). It mediates the interface by providing a moisture barrier flange that protects the transition zone, while its deflectable ribs accommodate the differential movement between the two materials, preventing cracking and moisture intrusion at this vulnerable interface.
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
The solution effectively reduces cracking of masonry coatings and prevents moisture from entering wall transitions, ensuring the longevity of both masonry and wooden structures by managing movement and drainage efficiently.
Implementation Method 1
the first flange defines a planar substantially non-perforated surface for providing a moisture barrier
Implementation Method 2
The first and second ribs 30, 32 of the expansion control joint 20 are symmetrical and deflectable for absorbing movement between the first and second masonry coatings 42, 44 during curing or other thermally induced expansion and contraction
Implementation Method 3
at least two ribs defined between the flanges provide the ability for the flanges to move relative to each other and thus accommodate expansion, contraction, or other slight movements between adjoining wall sections
Implementation Method 4
The rib 75 defines an extending portion 74 for supporting an applied masonry coating and a returning portion 76. The extending portion of the rib 75 begins generally adjacent the foundation transition 61 and tapers downwardly as shown. A drip edge DE is defined between the extending and returning portions 74, 76 of the rib 75
Data Source
AI summary
Various embodiments of the present invention are directed to a movement control screed that is structured for installation between first and second masonry coatings applied adjacent to a building wall. The movement control screed is structured as a control joint for absorbing movement between the first and second masonry coatings and also as a weep screed for accommodating drainage of water from behind the masonry coatings. The movement control screed comprises first and second flanges provided on opposite sides of first and second ribs.