A weep, a weep hole, or a weep-brick is a small opening that allows water to drain from within an assembly. Weeps are located at the bottom of the object to allow for drainage; the weep hole must be sized adequately to overcome surface tension.
Weeps may also be necessary in a retaining wall, so water can escape from the retained earth, thus lessening the hydrostatic load on the wall and preventing damage to the wall from the excess water weight and possible moisture damage from freeze/thaw cycles. In such cases the weeps may consist of a plastic, clay or metal pipe extending through the wall to a layer of porous backfill.
Typically, weeps are arranged to direct water which may have entered an assembly from outside, back to the outside. Weeps may also be found in metal windows and glazed curtain walls to permit interstitial condensation to escape. Automotive water pumps have weep holes to protect the bearings by letting out water that leaks past the seal. [1]
In building construction, weeps are typically found in a masonry veneer or cavity wall, just above the flashing. The cavity serves as a way to drain this water back out through the weep holes. The weep holes allow wind to create an air stream through the cavity. The stream removes evaporated water from the cavity to the outside. Weep holes are also placed above windows to prevent dry rot of a wooden window frame.
The open head joint process is done by leaving out mortar from the joints. This create open holes of the same size of the typical spacing of the joints. This is the most common method and most effective way to evaporate water from the cavity. The spacing between open head joints can be done at every 24 inches (61 cm). One of the problems with this method is that the open head joints create large holes which may not be appealing. Some maintenance workers may also inadvertently patch those holes up without realizing they are weep holes. There are some products such as aluminum vent and plastic grid that can be inserted into the weep holes to make them less conspicuous. [2]
Cotton wicks can be used to form weeps. A rope of up to 12 inches (30 cm) in length is placed in the joints. The other end of the rope is extended up into the cavity wall. The cotton can absorb the moisture inside the wall and wick it to the outside, but the converse is also true - it is possible for the cotton rope to wick a small amount of moisture from the outside to inside the wall. The process of evaporation is slower than with weep holes. Also, the cotton could catch fire. [2]
Another type of weep is a tube that can be made formed by using hollow plastic or metal. The spacing between the tubes is about 16 inches (41 cm) apart. The installation of the tubes are done at angle to allow water to drip out. If the angle is too steep, the opening hole inside the wall cavity will be too high for water to come out. If the angle is too flat, the mortar used in laying the bricks may drop into cavity and block the tubes. Sometimes a shallow layer of gravel is laid to prevent mortar dropping from blocking the tubes. The thickness of the plastic tube, however small, will create a small dam that allows water to pool inside the wall cavity.
Another technique to form tubes instead of using permanent tubing material is to use oiled rods or ropes. The oiled rod or ropes will be placed and mortared into the joints. The oil prevents mortar bond and the rods or ropes can be removed after the mortar is set, creating a hole similar to the use of a tube.
The advantage of the tube type is that it is less conspicuous. However, the small holes may not allow air to circulate and vent out the moisture very well. [2]
A newer weep technology uses corrugated plastic to create weep channels/tunnels that form the bottom side of the bed joint of mortar. These tunnels rapidly conduct the water out of the wall through multiple weep hole openings and ensure that the water can exit at the lowest point in the wall. Corrugated plastic weeps generally blend into mortar and are less conspicuous than rope weeps. [3]
Masonry is the craft of building a structure with brick, stone, or similar material, including mortar plastering which are often laid in, bound and pasted together by mortar. The term masonry can also refer to the building units themselves.
A chimney is an architectural ventilation structure made of masonry, clay or metal that isolates hot toxic exhaust gases or smoke produced by a boiler, stove, furnace, incinerator, or fireplace from human living areas. Chimneys are typically vertical, or as near as possible to vertical, to ensure that the gases flow smoothly, drawing air into the combustion in what is known as the stack, or chimney effect. The space inside a chimney is called the flue. Chimneys are adjacent to large industrial refineries, fossil fuel combustion facilities or part of buildings, steam locomotives and ships.
Mortar is a workable paste which hardens to bind building blocks such as stones, bricks, and concrete masonry units, to fill and seal the irregular gaps between them, spread the weight of them evenly, and sometimes to add decorative colors or patterns to masonry walls. In its broadest sense, mortar includes pitch, asphalt, and soft mud or clay, as those used between mud bricks, as well as cement mortar. The word "mortar" comes from Old French mortier, "builder's mortar, plaster; bowl for mixing." (13c.).
Grout is a dense fluid that hardens used to fill gaps or as reinforcement in existing structures. Grout is generally a mixture of water, cement, and sand, and is employed in pressure grouting, embedding rebar in masonry walls, connecting sections of precast concrete, filling voids, and sealing joints such as those between tiles. Common uses for grout in the household include filling in tiles of shower floors and kitchen tiles. It is often color tinted when it has to be kept visible and sometimes includes fine gravel when being used to fill large spaces. Unlike other structural pastes such as plaster or joint compound, correctly mixed and applied grout forms a water-resistant seal.
Stucco or render is a construction material made of aggregates, a binder, and water. Stucco is applied wet and hardens to a very dense solid. It is used as a decorative coating for walls and ceilings, exterior walls, and as a sculptural and artistic material in architecture. Stucco can be applied on construction materials such as metal, expanded metal lath, concrete, cinder block, or clay brick and adobe for decorative and structural purposes.
A concrete block, also known as a cinder block in North American English, breeze block in British English, concrete masonry unit (CMU), or by various other terms, is a standard-size rectangular block used in building construction. The use of blockwork allows structures to be built in the traditional masonry style with layers of staggered blocks.
In chemistry, efflorescence is the migration of a salt to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an internally held salt in water, or occasionally in another solvent. The water, with the salt now held in solution, migrates to the surface, then evaporates, leaving a coating of the salt.
A solar still distills water with substances dissolved in it by using the heat of the Sun to evaporate water so that it may be cooled and collected, thereby purifying it. They are used in areas where drinking water is unavailable, so that clean water is obtained from dirty water or from plants by exposing them to sunlight.
Repointing is the process of renewing the pointing, which is the external part of mortar joints, in masonry construction. Over time, weathering and decay cause voids in the joints between masonry units, usually in bricks, allowing the undesirable entrance of water. Water entering through these voids can cause significant damage through frost weathering and from salt dissolution and deposition. Repointing is also called pointing, or pointing up, although these terms more properly refer to the finishing step in new construction.
Exterior insulation and finish system (EIFS) is a general class of non-load bearing building cladding systems that provides exterior walls with an insulated, water-resistant, finished surface in an integrated composite material system.
Lime mortar or torching is a masonry mortar composed of lime and an aggregate such as sand, mixed with water. It is one of the oldest known types of mortar, used in ancient Rome and Greece, when it largely replaced the clay and gypsum mortars common to ancient Egyptian construction.
A kerosene heater, also known as a paraffin heater, is typically a portable, unvented, kerosene-fueled, space heating device. In Japan and other countries, they are a primary source of home heat. In the United States and Australia, they are a supplemental heat or a source of emergency heat during a power outage. Most kerosene heaters produce between 3.3 and 6.8 kilowatts.
A cavity wall is a type of wall that has a hollow center. They can be described as consisting of two "skins" separated by a hollow space (cavity). The skins typically are masonry, such as brick or cinder block. Masonry is an absorbent material that can slowly draw rainwater or even humidity into the wall. One function of the cavity is to drain water through weep holes at the base of the wall system or above windows. The weep holes allow wind to create an air stream through the cavity that exports evaporated water from the cavity to the outside. Usually, weep holes are created by separating several vertical joints approximately two meters apart at the base of each story. Weep holes are also placed above windows to prevent dry rot of wooden window frames. A cavity wall with masonry as both inner and outer skins is more commonly referred to as a double wythe masonry wall.
A wall plug also known as an anchor (US) or "Rawlplug" (UK), is a fibre or plastic insert used to enable the attachment of a screw in material that is porous or brittle or that would otherwise not support the weight of the object attached with the screw. It is a type of anchor that, for example, allows screws to be fitted into masonry walls. In US English, mentions of drywall anchors are sometimes meant to refer specifically to the type of plastic wall plugs with expandable wings for hollow walls, in contradistinction with mollies and toggle bolts.
Structural dampness is the presence of unwanted moisture in the structure of a building, either the result of intrusion from outside or condensation from within the structure. A high proportion of damp problems in buildings are caused by ambient climate dependent factors of condensation and rain penetration. Capillary penetration of fluid from the ground up through concrete or masonry is known as "rising damp" and is governed by the shape and porosity of the construction materials through which this evaporation-limited capillary penetration takes place. Structural damp, regardless of the mechanisms through which it takes place, is exacerbated by higher levels of humidity.
Damp proofing in construction is a type of moisture control applied to building walls and floors to prevent moisture from passing into the interior spaces. Dampness problems are among the most frequent problems encountered in residences.
Building insulation materials are the building materials that form the thermal envelope of a building or otherwise reduce heat transfer.
The tie in a cavity wall is a component used to tie the internal and external walls —constructed of bricks or cement blocks—together, making the two parts to act as a homogeneous unit. It is placed in the cavity wall during construction and spans the cavity. The ends of the tie are designed to lock into the mortar. Also incorporated into the design of the tie is means of preventing water transfer from the outer to the inner leaves. In flat ties, this can be a twist. In wire ties, this can be corrugations formed in the wire or again a twist.
Masonry veneer walls consist of a single non-structural external layer of masonry, typically made of brick, stone or manufactured stone. Masonry veneer can have an air space behind it and is technically called "anchored veneer". A masonry veneer attached directly to the backing is called "adhered veneer". The innermost element is structural, and may consist of masonry, concrete, timber or metal frame.
A rainscreen is an exterior wall detail where the siding stands off from the moisture-resistant surface of an air/water barrier applied to the sheathing to create a capillary break and to allow drainage and evaporation. The rainscreen is the cladding or siding itself but the term rainscreen implies a system of building. Ideally the rainscreen prevents the wall air/water barrier from getting wet but because of cladding attachments and penetrations water is likely to reach this point, and hence materials are selected to be moisture tolerant and integrated with flashing. In some cases a rainscreen wall is called a pressure-equalized rainscreen wall where the ventilation openings are large enough for the air pressure to nearly equalize on both sides of the rain screen, but this name has been criticized as being redundant and is only useful to scientists and engineers.