How to build a cinder block wall on a concrete slab - The poured concrete footing should be twice the width of the intended concrete wall.

 
Typical repairs for diagonal cracks in a <strong>concrete block</strong> foundation <strong>wall</strong> include the following steps. . How to build a cinder block wall on a concrete slab

Build your perimeter wall by laying blocks in mortar on top of the concrete. Concrete masonry blocks. Cement Types. It is faster and more efficient to construct a poured wall but can be expensive if the cement plant is far away. on top of the slab, along the wall that it is to be installed. Provide a clear area of at least 12 in. Poured Concrete Footing with Pier and Beam 3. Horizontal Cracks. Spread mortar on the footings (about ¾ inch thick), spreading only enough to accept three or four cinder blocks or use a trowel to mortar each block individually. Diy Cinder Block Fire Pit Ideas Plans Pros And Cons. Diy Building An Outdoor Fireplace You. Building weight load will dictate the size of the. Unlike a foundation with poured concrete footings, an on-grade foundation is constructed by stacking solid concrete blocks directly on the ground. Take out all of the dust, grime, and loose particles from the stones, and rinse them well if necessary. Make sure to remove Efflorescence (a white, powdery, crystal-like deposit) by using Drylok Etch or muriatic acid to clean the area. of Wall Area 75% of Wall Length give Block per Course Number of Courses = 1. Use an impact driver to drive a 3″ Tapcon screw through the wood and into the floor. How leaking cinder block basement walls are fixed. The average cost to build a concrete house is $280,000 to $430,000. Take up the block and spread mortar on the footing. The average cost to build a foundation is $9,260, with most homeowners spending between $5,128 to $19,350. In Australia, it is now common practice to fill all of the hollow cores with grout. Step 2. Plan Footing. The typical way I've seen that accomplished for a building that's already built would be to cast rebar into the slab that extends up out of the slab about 7" above the slab, aligned with the center of where the openings (cells) of the blocks will be. The practice of laying masonry units on a fresh, plastic concrete footing is commonly called "wet setting" or "first coursing. Building Cinder Block Walls - Everything You Need to Know. Use a shovel to mix the sand and cement until a uniform colour is achieved. TuffCrete Concrete Stain Paint. This is to workout exact slab dimension for the ground slab for oven builders in USA, Europe, Australia, Canada, New Zealand, Asia, Africa, South America, you name it where else. Scrub and then reapply. , a typical 8x8x16 block is actually 15-5/8 inches long and 7-5/8 inches high to accommodate the mortar joint). Raising block walls (and the slickest ash-drop design!) Image #0185 - cutting down one small left over wire mesh piece. the foundation also helps to keep the shed off the ground preventing dampness and rot. Never finish a concrete wall until the concrete is completely cured and dry. Block is not covered with siding on the outside and it is uncovered on the inside, with the block painted on the inside and outside faces. On top, if it is crushed stone or backfill, dirt is placed and leveled. Compute the implanted region length and denote the. Cinder concrete slab construction, also known as cinder arches, “goulash” construction, or even “short span arch construction”, was a type of reinforced . Made from concrete and coal cinders, they are lightweight and cheap. This concrete will flow down through the spaces in the. The walls will not be load bearing. 49 per square foot, with a range between $1. In large construction projects and more important projects. A poured concrete wall requires the construction of formwork and is, therefore, more labor-intensive. , a typical 8x8x16 block is actually 15-5/8 inches long and 7-5/8 inches. Use the string line as a guide for a straight row and lay the first cinder block layer. First it is necessary to prepare a solution for masonry. Just remember to give the wall enough time to cure before you apply plaster, distemper. The treated timber, if placed against the fence, will retain mositure & rot the fence. The existing concrete slab is level across the entire 34 foot of the back of the house but because of the slope of the grade, the wall ranges from ground level on the south side to some 36 inches above grade on the north side. Apply mortar to the sides of each block before stacking them. First, dig a trench in your desired spot so that you can lay base footing for your cinderblock wall. Building Cinder Block Walls - Everything You Need to Know. Use a shovel to cut around the blocks, marking the area where the grass and soil will be removed to construct the base of the bench. Deck Beams and Posts. Drill Pilot Holes Now, drill the pilot holes using a hammer drill. Don't force a blade into a cut. After the pump operator has gone around the wall perimeter once, he will make. Not only are cinder block houses relatively simple and. Forgetting about insulation for the moment, you could at least stick a 6 mil poly vapor barrier on the walls if that's where the moisture issue is coming from. level to level blocks lengthwise and a . The front of the carport was also framed in all the way to the slab. These concrete bases for the stem walls should be a minimum of 12 inches below the line of undisturbed soil and 12 inches below the frost line (or they should be frost protected). Uses for CMU Blocks. 21 thg 1, 2010. Convert the lengths to inches, divide by 16, and multiply by the number of block courses. Use a hammer drill with 3/16″ masonry bit to drill a hole through the wood and into the concrete floor. Grade C has a density greater than 1,000 kg/m3. Raising block walls (and the slickest ash-drop design!) Image #0185 - cutting down one small left over wire mesh piece. Learn how to build a low wall from concrete breezeblocks. Factor in the cost of labor and other material inputs and the total cost of constructing a cinder block house wall ranges between $9 and $12 per square foot. Made from. Make sure to clean any debris from the holes using a brush or vacuum. Set out the first row of cinder blocks without mortar, and adjust and move your wall as needed until you are satisfied with the layout. and the area of each concrete block (otherwise known as a cinder block or cmu): $$Block\,Area = Block\,Length \times Block\,Height$$ Calculating the Total Number of Concrete Blocks. A paint roller or brush made specifically for masonry is best. It is in fact one of the most used methods in the state of Florida and that’s hurricane country folks. 7 to 2. Here are some advantages of cinder block homes: 1. Install a CMU Block Wall: national average cost. Add 4”- 6” of depth for the gravel below the piers for drainage. How do I attach cinder blocks to concrete slab? Set out the first row of cinder blocks without mortar, and adjust and move your wall as needed until you are satisfied with the layout. 5″ concrete paver to create a stable base to build parallel column. Building a concrete block wall is one of the more involved building projects that requires careful planning and a little heavy lifting, but easy to . The idea here is to create a trench that you can place horizontal rebar into. 4- Use a lightweight faux stone that solves a wide range of hurdles. Spread the cement over the sand and add aggregates. Once the rebar has been placed, you will pour concrete on it as the actual retaining wall foundation. Concrete Block Garage Walls Journal Board. Get another demo / removal quote, $2500 is nuts. The poured concrete footing should be twice the width of the intended concrete wall. Shed Base. The existing concrete slab is level across the entire 34 foot of the back of the house but because of the slope of the grade, the wall ranges from ground level on the south side to some 36 inches above grade on the north side. Clutch power (the ‘grip’ between interlocking elements) provides enormous. Block and concrete are strong in compression, but weak in tension. It costs $565 on average to build a concrete or cinder block wall. The load will be carried by the timber frame sitting on pad stones set in foundation pits. For a long time, basement walls were built with cinder blocks. Do you need rebar in a block wall?. Unless otherwise required, footings should be carefully aligned so that the concrete masonry wall will be near the center line of the footing. 44, coming in between $12. It costs between $30 to $40 per linear foot to install a concrete wall with a concrete contractor. Ensure that you include a third layer of cinder blocks to keep the mesh grid in place. It costs $565 on average to build a concrete or cinder block wall. Applying a stucco finish to a concrete block wall · Marking concrete block positions on a slab with chalk · Bag of QuikWall · Setting the bottom cinderblock of a . 125 Block per sq. Hold the object you’re fastening firmly against the wall because the anchor will draw it only slightly tighter as you tighten the screw or nut. Next, pour some concrete mix on the rocks. Spread the cement over the sand and add aggregates. The edge of the slab is at least 6" on the side. on top of the slab, along the wall that it is to be installed. Labor typically. Footing Foundation. This will need to be completely filled with concrete to give you a nice square finished end. The fireplace will mount on a cinder block base on the foundation. Large Greenhouse. A poured concrete wall requires the construction of formwork and is, therefore, more labor-intensive. For example, a typical 8x8x16-in. Footing Size Chart Here are the minimum widths for concrete or masonry footings (inches):. Note the string-lines and the use of a form over a corner section to hold it in place as mentioned in the wet-set step-by-step instructions. Use a machine and pipe and fill them. A building constructed with concrete masonry blocks. You can use a product like RadonSeal Plus Penetrating Concrete Sealer to help waterproof and preserve the overall look of your wall. Take up the block and spread mortar on the footing. Stacking Basement Walls. Lay out your concrete block in a dry run, spacing it with 3/8-inch plywood spacers. 24 in. However, building cinder block walls does need some specific knowledge, which we will discuss today. Diy Cinder Block Fire Pit Ideas Plans Pros And Cons. How to build a cinder block wall on a concrete slab target donation request. Next, install the foundation pad in the trench by placing a crushed rock layer first, until it is even with the top of the trench. Wire mesh often ends up at the bottom of the slab, where it can't provide structural support. Then they Project Guides Bathroom Basement Deck & Patio Electrical Exterior Flooring Furniture Garage Gardening Hardware HVAC Kitchen Lawn Plumbing Roof Shed Trim Walls & Ceiling Woodworking Workshop Tools Tools by Brand (A-D) Black & Decker Bosch. The poured concrete footing should be twice the width of the intended concrete wall. These are normally the height of 2 or 3 cinder blocks and are always 3-sided so one can store firewood on one side. I used a 12″ x 12″ x 1. How To Repair Cinder Block Walls 12 Steps With Pictures. In large construction projects and more important projects. 375 x 8. 5″ concrete paver to create a stable base to build parallel column. Raising block walls (and the slickest ash-drop design!) Image #0185 - cutting down one small left over wire mesh piece. get your layout. Concrete Patio. These often feature built-in notches designed to hold beams, joists, and. Press the first block, a corner block, into the mortar. CMUs are some of the most versatile building products available because of the wide variety of appearances that can be achieved using them. Step 6 Butter the inside end of the first block and then press the block into the mortar bed to create a 3/8 inch mortar joint. Last, even after block masons have completed a wall, wood framing and carpenters are needed to build a second wall inside the CMU to accommodate mechanical piping and wiring. Fill in the area behind the wall rock with approved materials for below your patio. Use a shovel to mix the sand and cement until a uniform colour is achieved. Although the top surface of poured concrete footings should be relatively level, it should generally not be troweled smooth, as a slightly roughened surface enhances the bond between the mortar and concrete. Then, consider how tall you want your garage walls to be. The maximum weight supported by adhesive wall hooks is only eight pounds. See Table 1 and Figures 1 and 2 for details. For instance, a 10-by-8-by-16-inch concrete block made with stone dust may support more weight than a 15-by-12-by-24-inch block made with sand, because stone dust exhibits greater weight and strength than sand. How to Build a Block Wall Without Mortar: This video shows you how to build a dry stack, concrete block wall without mortar, using QUIKRETE QUIKWall Surface. Secure each course of blocks with a high-strength anchoring epoxy, staggering the joints. This is ideal for repairing foundation walls, laying sidewalks, creating steps and setting posts. Just how much cement? More than thirty 60-lb bags! Pluta admits that this step involved a LOT of work and heavy lifting. Step 1: Attach the Base Plate. Install the additional lengths of rebar where the vertical rebar uprights need to extend to the top of the concrete block wall. For example, if your greenhouse plan calls for an 8-by-12-foot greenhouse, add the width of the concrete blocks to the measure. The total price for labor and materials per square foot is $14. Footings and other load-bearing elements are added to the slab. Spread prepared roofing paper for waterproofing of your foundation bottom. Concrete house block walls are inexpensive, costing between $10 and $40 per square foot. Simply drill a hole into the concrete, hold the fixture you’re fastening over the hole, then use a hammer to tap the anchor into the hole. Four 2 by 4 inches stake. That is placed upright on the mortar mix, & then gently hammered into place. Press the first block, a corner block, into the mortar. I show you how to easily build cinder block steps over a weekend. Sprinkle water over the surface of the mixture. Build walls to a desired height, usually about 8 feet. QUIK-Tip: If you need to build a pad for the outdoor bar, use QUIKRETE 5000 Step 2 Snap a chalk line on each side of the intended block wall, to make sure the corners are square and the wall is straight. A pallet of "8-inch" CMUs. Concrete is being poured into a removable wall made of aluminum, wood, or steel. Use the pipe to fill up the gaps and hollow surfaces. Another view. In small projects such as garden walls, cinder blocks are used more frequently. A solution of 1 part muriatic acid to 12 parts water is quite good for efflorescence removal. Fill/tamp the place and verify the depth. Mix the mortar until it has the same consistency as toothpaste. Cinder block dimensions are typically 16 inches long, 8 inches high, and 8 inches wide. 4: Cinder block is lighter than concrete blocks. One sheet of 48 by 80 inches expanded metal sheet. It could be hard to find a contractor experienced at building concrete block homes. That's why you shouldn't dowel into the perimeter walls and glue the bars with epoxy. Note: Never backfill basement walls until the floor system is in place to support the tops of all walls from moving in from backfill pressure. Little or no digging is required to construct an on-grade foundation. Reinforced concrete foundations Reinforced concrete floor slab Waterproofing to floor and walls Egress windows (window well / light well) Staircase and roof opening. All to dry overnight or for a minimum of 12 hours between coats. Cinder block foundations do have advantages, like being able to hold more weight on top of the foundation. While some capstones can cost as little as $0. A simple little 900 square foot two-story cottage deep in the woods, built with block walls on a concrete slab. Laying the Concrete Blocks 1 Spread the mortar along the corner. Stage the first course of block, on top of solid, level concrete slab. Follow the shed manufacturer’s. 10 thg 4, 2015. Use a transit or a 4-ft. Logically, foundation damage and water penetration of a block foundation would be averted by preventing water from entering the concrete blocks in the first place. Step 1: Attach the Base Plate. 3 to 3. block would require a 16-in. Step 4: Add Finish Costs Cover the wall with a second thick coat and, if needed, a third coat. The cost to hire a masonry contractor is between $50 to $75per hour. 7 in. Building Cinder Block Walls - Everything You Need to Know. They are typically built with reinforced concrete or steel. If you are deciding to do this, check first if your wall can bear the weight that you are about to put and you would have to do some wall drilling to insert the holders of the hangings. DO NOT USE PEA GRAVEL. Step 3. Normal garages are around 9-10’ tall. There are a ton of things that you can do to make a concrete wall soundproof, even existing ones. To build a shed, you will need 20 to 60 blocks for the foundation, depending on the size of your shed. To estimate how much the walls will cost, find your wall area. They commonly come as self-aligning and trapezoidal in shape which makes it easier to form concaves, convexes, or straight walls. Fill in the area behind the wall rock with approved materials for below your patio. How To Build A Concrete Wall For Your Own Private Backyard Retreat. Then I'd construct a 8" CMU wall. Placing the blocks Follow the edges of the block laid from one finish to the next. Apr 10, 2022 · How do you build a cinder block wall? To construct a cinder block wall, begin by excavating a hole for the foundation and strengthening it by inserting steel rebar into each corner of the hole you dug. Download How to build a concrete block shed foundation. We have been able to use these products with confidence on our projects. How to Build a Retaining Wall and Pour a Concrete Slab Odell Complete Concrete 423K subscribers Join Subscribe 3K 156K views 1 year ago In this video we show you guys how to build a. Mark inside corner locations with chalk and snap chalk lines on the floor between marks to outline wall locations. . Sit at a table with the floor plan, and figure the lengths of the block walls. CMUs are some of the most versatile building products available because of the wide variety of appearances. Spread the cement over the sand and add aggregates. Fill all of the block cells. 5, you. The shim mix will need to have stone, larger stone as you get to the 4" thickness. Poured Basement and/or Crawl Space. Cinder block foundations do have advantages, like being able to hold more weight on top of the foundation. The fireplace will mount on a cinder block base on the foundation. Soundproof Drywall. Foundation walls to concrete slab on. Apr 10, 2022 · Step 2: Prepare the mortar according to the directions on the bag. Hollow blocks come in several types, which are. -It is not recommended to place. a task that is more complicated than simply laying new block on the slab, . S In Concrete Block Walls Complete Basement Systems. It does require. Cement Types. It does require. cojiendo a mi hijastra

$550 to $750 per m2 for concrete Besser blocks. . How to build a cinder block wall on a concrete slab

Clear the holes of all debris using compressed air, a shop-vac or wire brush. . How to build a cinder block wall on a concrete slab

There are a ton of things that you can do to make a concrete wall do to make a concrete wall. Snap a chalk line on each side of the intended block wall, to make sure the corners are square and the wall is straight. Cinder block foundations aren’t as popular as poured concrete block walls. 7 in. How to Build A Concrete Block Wall QUIKRETE 125K subscribers Subscribe 10K Share 5. The Energy Efficient Building Construction in Florida 7 th Edition lists the total R-Value for Concrete Block as follows: Unfilled 1. Cracks in the block or mortar joints; Seepage through the bottom of the blocks; Leaks between the floor slab and the foundation wall; Water coming up from below the floor slab; Water penetration around or below window frames and through basement windows; and. Concrete Block Construction (CMU) CMUs are cement blocks made from a mold in a factory. Once the bags are laid, you wet everything down thoroughly with a hose, saturating all of the bags. Cinder blocks are easy to carry and used in places where heavy loads are not put on. Cement Sonotube with Pier and Beam 4. , a typical 8x8x16 block is actually 15-5/8 inches long and 7-5/8 inches high to accommodate the mortar joint). A house with a basement starts with a hole. 888 = 1. Now we are confused. Ideally, a greenhouse should be located in a place that receives as much natural light as possible. Compute the blocks width Finish the demarcation work in the region through staking the width Complete the length for a three D (3D) figure/representation. Concrete lego blocks are made by pouring concrete into steel moulds. Apr 10, 2022 · How do you build a cinder block wall? To construct a cinder block wall, begin by excavating a hole for the foundation and strengthening it by inserting steel rebar into each corner of the hole you dug. Pour evenly to a depth of 4 inches. Has anyone heard of this before, and if so, how. On top of the rubble, waterproofing is put. Labor typically. Ensure that each side of the cinder block traces. Reinforcing steel needs to be in block walls - both vertical and horizontal. Factor in the cost of labor and other material inputs and the total cost of constructing a cinder block house wall ranges between $9 and $12 per square foot. get your layout. Some block foundations use concrete to fill in cinder blocks and rebar, although the concrete doesn’t need to be precisely poured and cured. Step 4. First, you should dug trenches for tape bases or settle pits for columnar ones. Step 4: Add Finish Costs Cover the wall with a second thick coat and, if needed, a third. Expanded Clay. block would require a 16-in. Lopang KHUTSOANE. You’ll need a solid base plate attached to the foundation unless you want to attach thin studs to the concrete block. Step 4. Tap the concrete with the flat side of the hoe. Then, when you set the blocks, you fill the cells that have rebar with cement grout. Having a sofa bench in your patio sounds so good since it can be a cozy spot to sit for some guests. Then, wash the. Use cement blocks to make a sturdy base and add the countertops. Begin the project by digging up the area where you are going to build your wall of cinder blocks. Mark all the edges of the course. The typical way I've seen that accomplished for a building that's already built would be to cast rebar into the slab that extends up out of the slab about 7" above the. There should be no nails below the area covered by the flashing tape. Draw an outline of the wall on the concrete with chalk, and then remove the blocks. Solution: Isolation clips and two layers of sheet rock with Green Glue between them, over 100% of the wall. The house exterior wall terminates at a concrete slab (over a basement) without proper sealing. . "In California and in most Western states, the Uniform Building Code (UBC) is the governing standard and there is a provision in Chapter 24, "Masonry," that states: "The initial bed joint (the mortar joint between the. The exact dimensions of footings will vary and will be determined in part by the type of soil at the site. Concrete Block Outdoor Fireplace. Accept all me Manage preferences. 5″ concrete paver to create a stable base to build parallel column. A concrete masonry unit ( CMU) is a standard-size rectangular block used in building construction. Once your footing is covered with the proper amount of cement, you can begin to dry stack the cinderblocks. You can also buy a ready dry mix (glue) which is diluted by simply adding water and stirred with a drill with a special nozzle. Modern Diy Fire Pit Easy Build. If you don't have the clearance, a layer of 30-pound roofing felt should work. INSTRUCTIONS TO BUILD A CONCRETE BLOCK GREENHOUSE FOUNDATION Step 1: Choose Your Greenhouse Location First, choose a location for your greenhouse and the greenhouse foundation. Paint the cinder block wall with a thick coat of masonry waterproofing paint, pusing paint into cracks and crevices of block. Save 1 - 7 of 7 Posts. Poured Concrete Footing with Pier and Beam 3. Building Cinder Block Walls - Everything You Need to Know. Rinse the. Free Fast. A building constructed with concrete masonry blocks. 8 Ways To Attach Things Cinder Block Walls. Jul 23, 2019 · Use "U" Shape lintel blocks mortar in place when the mortar is set drill thru block & into slab place rebar in holes place pea gravel cement mix in than water proof the exterior side. 5″ concrete paver to create a stable base to build parallel column. I used a 12″ x 12″ x 1. Select specialised deck blocks for patio posts and supports, or pier blocks for ground-level walkways and decks. This is a typical foundation wall (which almost assuredly has a footing beneath). There is limited separation between the home and the slab. Using the same process, set the opposite corner block. Typically a residential exterior wall made from CMUs measures 8″ x 8″ x 16″ and is 80 % hollow. below a flat roof, there was a cinder block ceiling- with cinder blocks. Set out the first row of cinder blocks without mortar, and adjust and move your wall as needed until you are satisfied with the layout. Spread prepared roofing paper for waterproofing of your foundation bottom. The house exterior wall terminates at a concrete slab (over a basement) without proper sealing. How leaking cinder block basement walls are fixed. 10 thg 4, 2015. Building a Retaining Wall with Concrete BlocksTG Building a Retaining Wall with Concrete BlocksHow To Build a Retaining WallPreferred Wall Building Tools:Dea. 8 thg 8, 2019. 97 each. A: To construct a block wall, you need to establish a solid footing that is a minimum of twice the width of the concrete block. The idea here is to create a trench that you can place horizontal rebar into. It costs $565 on average to build a concrete or cinder block wall. This is a lot more diy friendly and takes a lot less time than any of the other methods. Learn how to build a low wall from concrete breezeblocks. It is in fact one of the most used methods in the state of Florida and that’s hurricane country folks. Stage the first course of block, on top of solid, level concrete slab. Step2 Fantasy Vanity Canada Home Design Ideas Outdoor Stone Fireplaces Fireplace Plans Backyard. page aria-label="Show more" role="button">. The idea here is to create a trench that you can place horizontal rebar into. did they support the cinder blocks, and mortar them together despite. 7 to 2. Step 2. 8 thg 8, 2019. Place mortar within the traced lines using a trowel. [12] 5 Butter the "ears" of the second block with mortar. Log In My Account tr. It does require. Call for a professional foundation expert now. For high resolution video, visit: https://youtu. Butter one end of the block and set it next to the corner block. Use no more than two stones across the 36 inches width of the steps. Stay tuned for part 3 where we pour out the dr. 888 = 1. Setting Step 1 Measure and cut the rebar at about 8 inches in length--plus or minus an inch will not matter. The treated timber, if placed against the fence, will retain mositure & rot the fence. Concrete Block Foundation. Snap a chalk line on each side of the block wall as a reference line. 25 per square foot and the average size of a house is about 2,000 square feet. If you do the block there, I would suggest the same treatment for that so you know it is sealed right down to the slab. Remove excess . Make a design with the stones by arranging them accordingly. · Create Trench · Pour Concrete · Snap Chalk . I plan to insulate the cinder blocks on the inside with recycled ridged foam. Once you have the footing in place, apply a layer of surface bonding cement, then stack the first row of cinderblocks. The piers themselves have to be at least 6” above the ground level, plus the height of your wood frame. Here's the pier foundation. How long do cinder block houses last?. Step 2 Mix the mortar according to the directions on the package. Apr 10, 2022 · Step 2: Prepare the mortar according to the directions on the bag. This will ensure all the voids are filled and will also help to level the concrete. Step 3: Once the mortar has been mixed and is ready, lay a few shovels on a corner board to hold it in place. The installation of an interior perimeter drainage system. Search this website. For example, a typical 8x8x16-in. 4 thg 3, 2011. Log In My Account tr. Push the first block into the mortar until it's 3/8 inch above the footing. Not only are cinder block houses relatively simple and basic, they are also considered structurally sound and solid. Touching a sample piece of cinder slab in the field feels like a piece of pumice stone. . audrey itoni, market 32 pickup order, joi hypnosis, qpublic lancaster sc, merrjep shes blej gjithqka, st petersburg craigslist, registeroverridemethod d365 modified, brooke monk nudes twitter, craigslist pacifica, porn gay brothers, the intouchables english dubbed download, apartments for rent fairbanks ak co8rr