DIYdeals - Instructions for Raised Deck 5.0m wide x 4.1m
E-mail any questions to diydeals@hotmail.co.uk
Timber prices & Order form Decking Raised deck kit prices Welcome page
Raised deck joist layouts Ground deck joist layouts
1. For Raised Patio Decks 5.0m wide x 4.1m
Before starting erection of Deck
Please note that deck-boards and joists are the same grooved timber. The deck-boards may be used grooved side upwards or 'combed' side upwards - depending on your choice.
A. Marking out position of deck
i. Choose a site where the front to the deck will have the lowest step-up. The site can slope downwards up to 600 mm. Balustrade should be used on falls of over 300mm. Mark out the perimeter with pegs and line. Check for squareness by measuring for equal diagonals. Clear any obstructions that may interfere with the deck or pergola - ground levelling is not required as the posts will be used to level the deck.
ii. Mark out where the Metal Post Anchors will be positioned (see plan above) (please read the Pergola assembly instructions first if fitting a pergola over the raised deck- see note no. 4 below) - when in place they will have their bolts facing to the front. (That is the bottom of the drawing) Check for squareness of the post anchors by measuring for equal diagonals.
B. Driving Post Anchors into the ground, cutting and fixing Posts
i. Cut a short piece of post to use inside the Post Anchors when driving them into the ground. With the Bolts facing the front drive the Anchors into the ground continually checking and adjusting for uprightness and squareness. Care will be needed to ensure that each set of three posts are in line by laying down a deck board flat along the run of 3 posts. When all nine have been hammered into position, choose the posts on the highest ground (i.e. the one that will be the lowest step up) and place a Support Joist upright against the 2 Post Anchors running front to back raised off the ground approx. 30 mm at the front (use a board laid flat) - level the joist and temporarily support at the back (another way is to temporarily hold in place with a deck screw). Repeat for Support Joist on the other side of the post. Repeat for the other 2 sets of Post Anchors. Once they are all temporarily in place check the joists are level, mark out where the posts will be cut and remove from the temporary fixings.
ii. Cut the posts so that there will be 9 short posts each coming in line with the top of the Support Joists from the base of the Post Anchor. Make cuts with a slight fall from front to back. Brush Preserver onto the cut surfaces of the Posts
iii. Fix Posts into Post Anchors (where possible, ensure cut edge is at the top with the fall from front to back to assist clearing rainwater). Posts may require easing to fit the Post Anchors -Brush Preserver onto the cut surfaces -Check verticals & tighten the bolts on the Post Anchors to ensure good grip. It is advisable to concrete in the Post Anchors after fixing all the joists.
2. Fixing Support Joists to Posts
A. Select the 6 strongest joists with the fewest and smallest knots for use as Support Joists.
i. Ensure that the first 2 Support Joists will be fixed to the front Post which will be on the highest ground. (i.e. the one where the Support Joist will be nearest the ground and preferably the front entrance to the Deck). Place the first Support Joist on the outside and second Support Joist on the inside of the 3 Posts running from front to back - so that there is an equal projection from both Posts. Position these first 2 Support Joists against first set of Posts, and re-level as before by temporarily fixing with deck screws. In the front Post, use the Drill Bit provided to make a hole all the way through the joists, the metal socket and the post - drill the hole 40 mm from the bottom of the Support Joist and 10 mm offset from the centre of the post. Do not drill the second hole into the same post yet because it is necessary to create the levels with all the other Posts and Support Joists first. Temporarily fix both Joists to the Post with a Bolt.
ii. Checking that the level of the first 2 Support Joists are correct, position them against the back Post and drill, as (2Ai). You may not be drilling through the metal of the Post Sockets if there is a slope. After rechecking level, repeat the drilling for the lower bolt in the centre post.
iii. Using one of the other timbers as a straight edge, align & level the next 2 Support Joists with first 2 Support Joists and position against the second front Post matching projections and drilling as (2Ai). Checking that the levels of these 2nd 2 Support Joists are correct, position them against the 2nd back Post and drill as (2Ai). After rechecking level, repeat the drilling for the lower bolt in the centre post. Check that the Joists attached to 1st 2 Posts are level with those attached to 2nd 2 Posts. Adjust if necessary.
Using one of the other timbers as a straight edge align & level the next 2 Support Joists with both the other 2 sets of Support Joists and position against the third front Post matching projections and drilling as (2Ai). Checking that the levels of these 3rd 2 Support Joists are correct, position them against the 3rd back Post and drill as (2Ai). After rechecking level, repeat the drilling for the lower bolt in the centre post. Check that the Joists attached to all 3 sets of posts are level. Adjust if necessary.
B. Drilling a second hole in each post, Fixing the Washers and tightening the Bolts
i. When all Support Joists are level - Drill a second hole 40 mm from the top of the Support Joists and 10 mm offset the other way from the centre of each post. Do this for all Posts. You may not be drilling through the metal of the Post Sockets for these upper holes - if you have this situation - Mark the Posts at the top of the Joists. Remove all Bolts and the Support Joists from their temporary fixings. Keep by the Posts. Position Washers where necessary, in between the Posts and the Support Joists to compensate for the gaps created by the Post Anchors, push all 8 Bolts through the Support Joists, Posts and Post Sockets using a washer against the joist at the back before tightening the nut - ensuring the washers have sunk a little into the joists.
3. Fixing Outer & Centre Joists
A. Hanging Front & Rear Joist from Support Joists
i. Position Front Joist against front of all 6 Support Joists and ensure equal projections from both outside Support Joists. Place 6 Joist Hangers so that they rest on top of all 6 Support Joists i.e. open end pointing downwards with the back against Front Joist and when correctly aligned - flush with the top of the Support Joists and with equal projections - mark the positions on Front Joist where the 6 screws in each Hanger will be fixed. Remove and fix the hangers to Front Joist using the Small Screws. To give maximum strength the screws will be a tight fit and may need ‘starting’ with a tap from a hammer. Place Front Joist over Support Joists so that it rests on the Hangers - secure to all 6 Support Joists by screwing into the timber on one side.
ii. Repeat for Rear Joist
B. Fixing the Side Joists to Front & Rear
Joists and Hanging the Centre Joists
i .Lay the Side Joists on the ground with the inside face pointing upwards. Position the longer side of the Corner Brackets on the Side Joists so that they are flush with the end and are 20 mm in from the top & bottom. Use 3 of the Screws to fix each Corner Bracket to the Side Joists. Ensure that the tops of all Joists are flush and fix the Side Joists, using Small Screws, into each end of the Front & Rear Joists - this can be flush (especially when joining two decks together) or, if a single deck, up to 60mm in from each end to provide an overhang for the deck boards.
ii.
Mark the Positions of the 2 sets of 2 centre rails on the Front & Rear Joists
spaced approx. as above drawing. Position the remaining 4 Hangers at the bottom of the Front & Rear
Joists centrally across each of the 2 marks with the open end pointing upwards,
so that the Centre Joist will later rest on the Hangers. Fix the
Hangers with the 6 Small Screws onto the Front & Rear Joists. Drop the
Centre Joists into place - and secure by screwing into the timber on one side.
C. Fixing Noggins between Support Joists
i. Cut the 32 x 100 sawn timber noggins to fit between all joists in line with the centre posts (marked in red in the drawing above) and Brush Preserver onto the cut surfaces. Position them in line with the bottom of the Support Joists. Leaving a gap of at least 40 mm from the top of the Support Joists ensures the deck board clips will not snag. Corner brackets are supplied for the 2 outside joists so that screws will not show and for the rest skew screw through the noggin into the joists.
Noggins are used to prevent distortion on the Support Joists and should not be left out.
D. Before fixing Balustrade and/ or Deck Boards concrete around post sockets. Dig out approx. 400 mm deep and 600 mm square around each post socket, this is best done in 3 stages - first to the centre 3 post anchors and, after adding concrete, then the 2 outside middle post anchors and after adding concrete again recheck they are levels and after allowing time to partially set then do the 4 outside posts, recheck they are level and fill the remaining 4 holes with concrete. It is important this is done especially to the centre joists as there is a lot of weight to spread over these posts.
4. If using pergola - click here N.B. Always fix Pergola Posts, Supports, and Tops before fixing Deck boards
5. If using Balustrade - click here Please note that the newel posts must be fitted before Deck boards
6. Fixing the Deck Boards - 28 are required to cover 4.1m
A. i. Position the first deck board approx 25mm over and ensure it is flush at the ends of the front joist. Screw in 2 decking screws in line with each joists the front one going into the front joist.
ii. Space out the deck boards with a 3 to 4mm gap between the deck boards and ensure flush at the ends with the board in front. Screw in 2 decking screws approx. 25mm from the front and back in line with each joists.
iii. The back board should overlap the back joists by approx. 25mm.
7. Finishing & Maintenance
i. As all timbers are pressure preserved further treatment is not necessary and the timber will fade to a natural grey colour. If preferred, the deck may be coated with Decking Stain to the colour of your choice. If there is any build of moss, after winter use an anti-fungicidal and hose down to remove. To restore the colour apply a further coat of Decking Stain.
ii. Dispose of all waste timber in your dustbin - do not burn. Wash hands after handling timber - especially before eating. Always wear safety glasses when using power tools.
Help Line -
For more information - contact Peter Dale on 01457 855259
All rights reserved. 04/01/2008.
You may print this copy for use during erection. This leaflet may not be reproduced in whole or in part without the prior written approval of Peter Dale.
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