Bridging thermal block system and method

A system and method for insulating a metal roof include a blanket of insulation laid over at least one purlin. A series of thermal blocks are fastened above the purlin over the blanket of insulation. Each thermal block in the series of thermal blocks has legs that pin the blanket of insulation to a top of each purlin. Gaps are defined between the legs, the gaps enabling regions between the legs wherein the blanket of insulation is only partially compressed between the purlin and an underside of each thermal block. Each thermal block can include a first end, a second end, and a first leg between the first and second ends. The first end includes slots for receiving clip legs of a first roof clip. The second end includes an abutment surface and a landing surface for receiving a next thermal block in a series of thermal blocks.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to the field of roof structures and related methods. More specifically, the invention relates to the field of insulating metal roofing structures.

2. Description of the Related Art

Roof insulation has been used in metal building arrangements. A typical roof insulation configuration uses blanket insulation. The thermal resistance offered by the insulation is compromised when it is compressed or packed down. In conventional metal roof insulation systems, when the roof structure is applied to the tops of the roof purlins, the thick layer of blanket insulation is compressed, thus reducing the thermal resistance of the roof insulation system. In some areas of the conventional roof system, the compression of the insulation is so severe that a thermal short is created, thus substantially degrading the insulation properties of the roof insulation system.

SUMMARY

According to a first aspect, the present disclosure provides a thermal block for a metal roof, the thermal block comprising a first end, a second end, and a first leg between the first and second ends. The first end includes slots for receiving clip legs of a first roof clip. The second end includes an abutment surface and a landing surface for receiving a next thermal block in a series of thermal blocks.

According to another aspect, the present disclosure provides a system comprising a blanket of insulation laid over at least one purlin. A series of thermal blocks are fastened above the purlin over the blanket of insulation. Each thermal block in the series of thermal blocks has legs that pin the blanket of insulation to a top of each purlin. Gaps are defined between the legs, the gaps enabling regions between the legs wherein the blanket of insulation is only partially compressed between the purlin and an underside of each thermal block.

According to another aspect, the present disclosure provides a method of providing insulation in a metal roof, the method comprising: laying a blanket of insulation over at least one purlin; fastening a series of thermal blocks above the purlin over the blanket of insulation, each thermal block in the series of thermal blocks having legs that pin the blanket of insulation to a top of each purlin; and forming gaps between the legs, the gaps enabling regions between the legs such that the blanket of insulation is only partially compressed between the purlin and an underside of each thermal block.

DETAILED DESCRIPTION

Embodiments of the present invention provide systems and methods for providing insulation for a metal roof.

One embodiment is depicted inFIGS. 1,2A-E, and3. Referring first toFIG. 1, a broken out portion of a roof incorporating an embodiment of the system is illustrated in perspective. The system100is provided to support and insulate roof panels102which will be installed on top of the assembly. The system rests on top of a plurality of Z-purlins104. Although only three Z-purlins are shown inFIG. 1, it should be understood that many more of these purlins in parallel relation would be included on various roof structures on a building.

In cross-section, the Z-Purlins typically have a vertical web portion300(seeFIG. 3) and horizontal top flange302and bottom flange306portions. The horizontal top flange302has a downwardly sloped front lip304. The bottom flange portion306of purlin104has an upwardly angled lip308, and the bottom306extends in an opposite direction than does the top flange portion302. Although the system can be used with different kinds of purlins (e.g., C-shaped and other varieties), the purlins104shown inFIGS. 1 and 3are Z-shaped, and are, therefore, referred to as Z-purlins. The roof frame also includes a plurality of angle-metal cross members110which are installed in an offset staggered fashion through alternating opposed sets of apertures111in the webs300of the purlins104in a known manner.

Initially, two opposing strips of batt insulation108aand108b, each having laterally extending flaps107aand107bon each side, are unrolled over and rest on top of the cross members110in the space existing between the opposing purlins. Then, extended portions107aand107bare draped over each on top of the upper flange302of the purlin as can be seen inFIG. 3. The opposing batts of insulation108aand108beach run between and in the direction of the purlins104as shown in the figures. Insulation108, in embodiments, is a fiberglass insulation (often marketed in rolls) which is commonly used to insulate floors, walls and ceilings. This insulation typically comes with a vapor barrier sheet already installed on the underside of the roll. The laterally extending flaps are a deviation from the norm, but are a feature easily included by the manufacturer. Although most commonly made of fiberglass, insulation108could also be constructed of other insulating materials.

When these strips of insulation108are unrolled in place between the purlins, the insulation is not compacted in any way, allowing it to maintain full thermodynamic properties. And this freedom from encumbrance will be maintained in the final product.

Once the insulation strips108have been unrolled in the space between the purlins, and the flaps107aand107bhave been draped over the purlin upper flange, a blanket of insulation112is laid into place over the purlins (as seen inFIG. 1). This insulation, in embodiments, is constructed of fiberglass, but could be made from any number of materials depending on the application. This blanket112is held down by the bridging blocks114.

Each series of bridging blocks114is installed such that it runs longitudinally along the upper portions302of each Z-purlin102as shown inFIG. 1. The bridging blocks have a number of features, the details of which can be seen inFIGS. 2A-Ein which a single block is shown.

As seen inFIGS. 2A and 2B, each bridging block114includes an intermediate leg116and a joint supporting leg118. A first end200of each block includes two clip-leg-receiving notched out vertical slots208. These slots208can be seen most clearly in the end view (FIG. 2D) of the first end200, and in the Section2E-2E shown inFIG. 2E. These slots208are designed to receive legs314(seeFIG. 3) at each of the joints130(seeFIG. 1) to avoid clip/block interference.

A second end202of each bridging block (seeFIGS. 2A,2B, and2C) includes a landing surface204as well as an abutment surface206for receiving the corresponding first end200of the next block in the series. But before the first end200for the next block in the series is received, an L-bracket122is installed. A short portion212of the L-bracket122is sized to fit the abutment surface206, and the longer portion210of the L-bracket122is sized to match the landing surface204. These end configurations, along with the clips120and L-brackets122enable the installation of a series of continuous blocks in series one after the other, and each block114, in the disclosed embodiment, is identical. Alternatively, these blocks could have different configurations for different embodiments.

Referring toFIG. 1, a first series126of blocks114have already been installed, whereas a second series128of bridging blocks114are in the process of being installed. The blocks114in series126and128inFIG. 1come together at joints130. The joints130are formed by the meeting of the second end202of an already installed block, e.g. block132, and the first end202of the next block, e.g., block134, in the series to be installed. Block132(FIG. 1) has already been fastened to the purlin104, and block134is shown about to be fastened at its end202using L-bracket122and clip120.

The L-bracket122, when installed, will clamp down on the landing surface204at end202when the particular clip120at that joint130is screwed down using two fasteners316. One of these fasteners316can be seen inFIG. 3. Although only one fastener of the pair316can be seen inFIG. 3, it should be understood that two exist and that the second is simply hidden behind the first. These fasteners could be a bolt315/nut317combination as shown, or alternatively can be screws. Although a bolt arrangement is shown, screws are preferred. Prefabricated, e.g., punched or drilled, holes (not shown) can exist in the bottom of the clip120in one embodiment. The fasteners316are installed through these holes, then through predrilled or prepunched holes (not shown) made through the landing portion210of the L-bracket122, then through predrilled or prepunched holes (not shown) made through the joint support leg118of the block114, through the insulation blanket112and the flaps107aand107b, and then through predrilled or prepunched holes made into the purlin head302. SeeFIG. 3. In any instance, predrilling will not be required through the107aand107bor the blanket of insulation112, because both are easily pierced by the fastener316. Where screws are used, the predrilled or prepunched holes are optional. Additionally, where predrilled holes or prepunched are used in the purlin head302, they will be sized to be slightly smaller than the diameter of the screws to encourage engagement into the head302.

Regardless of the fastening device used (bolt or screw), the fastening causes the L-bracket122to clamp down on the landing area204of block134, and not only is second end202of block134held down, but the first end of that same block134is thus caused to rest into its joint with the already installed block132.

Now that the second end202of block134has been secured by the clip and L-bracket installed there, the clip legs208and seam flanges310will stick up and are exposed. Then, in order to install the next block136, the slots208of its first end200are matched up with and consume the clip legs314of the clip already installed on the last block134. Then, when the clip120and L-bracket122are screwed down onto the landing area204of block136, the joint between blocks134and136is complete. It will be understood that block after block can be installed in series this way until the entire length of a purlin104is reached.

As the blocks in each series are secured, the flaps107aand107band a small swatch of the insulation blanket112are pinched between the underside of each block114and the purlin head302. More specifically, the bottom surfaces212and214of each of the legs116and118on each block, respectively, directly clamp down on the blanket112and flaps107aand107b.

Gaps150(see series126inFIG. 1) formed by underside surfaces216between the legs116and118on each bridging block, however, allow for some expansion of the insulation in that area. Thus, although somewhat restricted in volume, the insulation blanket between the block legs still has some depth, and is not completely compacted. This provides heat transfer resistance advantages. Laterally relative to each row of blocks114, the blanket expands upward back to its normal density and fills the area above the upper surfaces350of the lower insulation strips108to be at the same levels as the upper surfaces of the installed blocks114.

Next, the metal roof panels102are installed over and transversely to the blocks. More specifically, the flanges310on top of the clips120are seamed into edges124and125of the roof panels102in a known manner. Although only a single roof panel is shown inFIG. 1, those skilled in the art will be aware that a plurality of roof panels will be installed such that the entire roof is covered.

Another embodiment is depicted inFIGS. 4-5. The embodiment ofFIGS. 4-5uses the same bridging block configuration shown inFIGS. 2A-E, so detailed description of this element of the disclosed roof system has not been repeated. Referring first toFIG. 4, a broken out portion of a roof incorporating this second embodiment is illustrated. Again, the system400is provided to support and insulate roof panels403which will be installed on top of the assembly. Again, the system rests on top of the plurality of Z-purlins500. Although only three Z-purlins500are shown inFIG. 4, it should be understood that many more of these purlins500in parallel relation would be included on the entire roof structure.FIG. 5shows the system400of the second embodiment in cross-section. The Z-Purlin500has a vertical web portion501(seeFIG. 5) and horizontal top portion502and a bottom portion506. The horizontal top portion502has a downwardly sloped front lip504. The bottom portion506of purlin500has a lip508, and the bottom506extends in an opposite direction from the direction of the top portion502. Although the second embodiment400of the system can be used with different kinds of purlins (e.g., C-shaped and other varieties), the purlin cross sections shown inFIGS. 4 and 5are Z-shaped. As with the last embodiment, the roof frame will also include a plurality of angle-metal cross members110which are installed through apertures in the webs501in the purlins500in a known manner.

Initially, a blanket of insulation558is laid out over the purlins500such that it sags down to rest atop the cross members110. This is different than with the first embodiment which had thin batts108which were unrolled and extended longitudinally between the opposing purlins104. Here instead, the blanket is draped over all. Insulation blanket558, in the embodiments ofFIGS. 4 and 5, is a fiberglass insulation (often marketed in rolls) which includes a vapor barrier sheet556on its bottom side. Although most commonly made of fiberglass, blanket558could be constructed of other materials. Further, vapor-barrier sheet556and blanket558could be separate components, the blanket laid on top of the sheet.

Once blanket558has been laid into place over the purlins500, the bridging blocks414are installed directly on top of the upper portion302of each Z-purlin500as shown inFIG. 4.

Referring toFIG. 4, a first series426of blocks414have already been installed, whereas a second series528of bridging blocks414are in the process of being installed. The blocks414in series426and528shown inFIG. 4come together at joints430. The joints430are formed by the meeting of the second end402of an already installed block, e.g. block432, and the first end401of the next block, e.g., block434, in the series to be installed. Block432(FIG. 4) has already been fastened to the purlin500, and block434is shown about to be fastened at its end402using L-bracket422and clip420.

Here however, since the blanket558of insulation is already draped across the purlin heads, the L-brackets422, when installed, will clamp the leg bottoms of the bridging blocks414down on top of a small patch of insulation on the purlin heads.

Prefabricated/drilled holes (not shown) exist in the bottom of the clip420in the preferred second embodiment. A bolt515nut517combination (seeFIG. 5), or a screw could be used to fasten. The fasteners516are installed through these holes, then through the larger portion of the L-bracket422(see, e.g., portion210inFIG. 2), then through the joint support leg518of the block414, and then into the purlin500. SeeFIG. 5.

Two holes (not shown) can be predrilled or prepunched down through the landing portion (see e.g.210inFIG. 2) of the L-bracket422, predrilled or prepunched bores made through the leg518of the bridging block414, then through the thin layer of blanket insulation which has been compressed below the leg518, and then down to predrilled or prepunched holes on the purlin head502. With the bolt version the bolts have lengths which cause the bolt tips to drop through the leg518, through the insulation, and then drop underneath the purlin head502(seeFIG. 5) where the nut517can be screwed on. Where the fastening mechanisms516are self-drilling screws they will be passed down and then secured through the holes in the upper surface502of the Z-purlin500below which when screws are used, will have diameters slightly smaller than the screws selected so that they can bite. This causes the L-bracket422to clamp down on the landing area (e.g., see area204inFIG. 2B) of block414.

Now that the second end402of block434has been secured by the clip420and L-bracket422installed there, the clip legs511and seam flanges510will stick up and are exposed. Then, in order to install the next block436, the slots508of its first end401are matched up with and consume the clip legs511of the clip already installed on the last block434. Then, when the clip402and L-bracket422are screwed down onto the landing area of block436, the joint between blocks434and436is complete. It will be understood that block after block can be installed in series this way until the entire length of a purlin500is reached.

As the blocks in each series are secured, the lower batt insulation sheet558and vapor barrier556are pinched between the underside of each block414and the purlin upper flange502. More specifically, the bottom surfaces (e.g., bottom surfaces212and214inFIG. 2) of each of the legs514and518on each block, respectively, directly pinch the insulation blanket558to the upper surface of each purlin head502. In gaps450(see series426inFIG. 4) formed between the legs514and518on each block, however, the insulation, although somewhat restricted in volume, is partially puffed out. This provides heat transfer resistance advantages. The upper surface of the insulation550(seeFIG. 5), other than where it is pinched underneath the legs514and518, is substantially maintained at a level equal to the surfaces underneath the blocks414.

Once all of the blocks414have been secured, a relatively thin strip of batt insulation412is unrolled into the rectangular cavities formed between the opposing series of blocks, e.g., between series426and528where the insulation extends longitudinally, as shown inFIG. 4. Board insulation could be used instead of batt insulation in embodiments. The upper insulation layer412, if made from board insulation, will be precut to fit the cavities. Where rolls of batt insulation are used, they are normally sized in width to fit between standard purlin spacing. There, the upper insulation layer412sits on top of the upper surface550of the lower blanket and fills the open area between the rows of blocks above the lower blanket558, as shown inFIG. 4.

Once the relatively thin strips of batt insulation412are laid in place, the metal roof panels403are installed over and transversely to the blocks414. More specifically, the flanges510on top of the clips420are seamed into edges424and425of the roof panels403in a known manner. Although only a single roof panel is shown inFIG. 4, those skilled in the art will be aware that a plurality of roof panels will be installed such that the entire roof is covered.